diff --git a/.gitignore b/.gitignore
index f0e3bcacb9..e0f63a0998 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 /target
-**/*.rs.bk
\ No newline at end of file
+**/*.rs.bk
+**/*.un~
+**/*.toml~
\ No newline at end of file
diff --git a/Cargo.lock b/Cargo.lock
index 7111148ff6..d42147a967 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,27 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "ansi_term"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "ctor"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "difference"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "logos"
 version = "0.9.7"
@@ -20,6 +42,25 @@ dependencies = [
  "utf8-ranges 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "output_vt100"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pretty_assertions"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ctor 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "output_vt100 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "0.4.30"
@@ -28,6 +69,14 @@ dependencies = [
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "proc-macro2"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "quote"
 version = "0.6.13"
@@ -36,6 +85,14 @@ dependencies = [
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "quote"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex-syntax"
 version = "0.6.12"
@@ -46,6 +103,7 @@ name = "rusty"
 version = "0.1.0"
 dependencies = [
  "logos 0.9.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -58,22 +116,68 @@ dependencies = [
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "syn"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "unicode-xid"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "unicode-xid"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "utf8-ranges"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "winapi"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [metadata]
+"checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+"checksum ctor 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "cd8ce37ad4184ab2ce004c33bf6379185d3b1c95801cab51026bd271bf68eedc"
+"checksum difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
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+"checksum output_vt100 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "53cdc5b785b7a58c5aad8216b3dfa114df64b0b06ae6e1501cef91df2fbdf8f9"
+"checksum pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3f81e1644e1b54f5a68959a29aa86cde704219254669da328ecfdf6a1f09d427"
 "checksum proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)" = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
+"checksum proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "9c9e470a8dc4aeae2dee2f335e8f533e2d4b347e1434e5671afc49b054592f27"
 "checksum quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)" = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
+"checksum quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "053a8c8bcc71fcce321828dc897a98ab9760bef03a4fc36693c231e5b3216cfe"
 "checksum regex-syntax 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)" = "11a7e20d1cce64ef2fed88b66d347f88bd9babb82845b2b858f3edbf59a4f716"
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 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
+"checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
 "checksum utf8-ranges 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b4ae116fef2b7fea257ed6440d3cfcff7f190865f170cdad00bb6465bf18ecba"
+"checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
+"checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+"checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/Cargo.toml b/Cargo.toml
index 07fbe07d17..2404f7df2c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,3 +6,6 @@ edition = "2018"
 
 [dependencies]
 logos = "0.9.7"
+
+[dev-dependencies]
+pretty_assertions = "0.6.1"
diff --git a/src/ast.rs b/src/ast.rs
index 9f39c094ee..2df56037f2 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -46,7 +46,12 @@ pub enum Operator {
     Minus,
     Multiplication,
     Division,
-    OperatorEqual,
-    OperatorNotEqual,
+    Equal,
+    NotEqual,
     Modulo,
+    Less,
+    Greater,
+    LessOrEqual,
+    GreaterOrEqual,
+
 }
diff --git a/src/lexer.rs b/src/lexer.rs
index 33d9e877ac..9e4867d4d8 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -57,6 +57,18 @@ pub enum Token {
     #[token = "<>"]
     OperatorNotEqual,
 
+    #[token = "<"]
+    OperatorLess,
+
+    #[token = ">"]
+    OperatorGreater,
+
+    #[token = "<="]
+    OperatorLessOrEqual,
+
+    #[token = ">="]
+    OperatorGreaterOrEqual,
+
     #[token = "MOD"]
     OperatorModulo,
 
@@ -133,7 +145,7 @@ mod tests {
 
     #[test]
     fn operator_test() {
-        let mut lexer = super::lex("+ - * / MOD");
+        let mut lexer = super::lex("+ - * / MOD = <> < > <= >=");
         assert_eq!(lexer.token, super::Token::OperatorPlus);
         lexer.advance();
         assert_eq!(lexer.token, super::Token::OperatorMinus);
@@ -143,6 +155,18 @@ mod tests {
         assert_eq!(lexer.token, super::Token::OperatorDivision);
         lexer.advance();
         assert_eq!(lexer.token, super::Token::OperatorModulo);
+        lexer.advance();
+        assert_eq!(lexer.token, super::Token::OperatorEqual);
+        lexer.advance();
+        assert_eq!(lexer.token, super::Token::OperatorNotEqual);
+        lexer.advance();
+        assert_eq!(lexer.token, super::Token::OperatorLess);
+        lexer.advance();
+        assert_eq!(lexer.token, super::Token::OperatorGreater);
+        lexer.advance();
+        assert_eq!(lexer.token, super::Token::OperatorLessOrEqual);
+        lexer.advance();
+        assert_eq!(lexer.token, super::Token::OperatorGreaterOrEqual);
     }
 
     #[test]
diff --git a/src/parser.rs b/src/parser.rs
index ded89c1360..163d67b808 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -114,18 +114,18 @@ fn parse_statement(lexer: &mut RustyLexer) -> Result<Statement, String> {
 }
 
 fn parse_primary_expression(lexer: &mut RustyLexer) -> Result<Statement, String> {
-    parse_additive_expression(lexer)
+    parse_equality_expression(lexer)
 }
 
 fn parse_equality_expression(lexer: &mut RustyLexer) -> Result<Statement, String> {
-    let left = parse_compare_expression(lexer);
+    let left = parse_compare_expression(lexer)?;
     let operator = match lexer.token {
         OperatorEqual => Operator::Equal,
         OperatorNotEqual => Operator::NotEqual,
         _ => return Ok(left),
     };
     lexer.advance();
-    let right = parse_primary_expression(lexer)?;
+    let right = parse_equality_expression(lexer)?;
     Ok(Statement::BinaryExpression {
         operator,
         left: Box::new(left),
@@ -134,7 +134,21 @@ fn parse_equality_expression(lexer: &mut RustyLexer) -> Result<Statement, String
 }
 
 fn parse_compare_expression(lexer: &mut RustyLexer) -> Result<Statement, String> {
-
+    let left = parse_additive_expression(lexer)?;
+    let operator = match lexer.token {
+        OperatorLess => Operator::Less,
+        OperatorGreater => Operator::Greater,
+        OperatorLessOrEqual => Operator::LessOrEqual,
+        OperatorGreaterOrEqual => Operator::GreaterOrEqual,
+        _ => return Ok(left),
+    };
+    lexer.advance();
+    let right = parse_compare_expression(lexer)?;
+    Ok(Statement::BinaryExpression {
+        operator,
+        left: Box::new(left),
+        right: Box::new(right),
+    })
 }
 
 fn parse_additive_expression(lexer: &mut RustyLexer) -> Result<Statement, String> {
@@ -145,7 +159,7 @@ fn parse_additive_expression(lexer: &mut RustyLexer) -> Result<Statement, String
         _ => return Ok(left),
     };
     lexer.advance();
-    let right = parse_primary_expression(lexer)?;
+    let right = parse_additive_expression(lexer)?;
     Ok(Statement::BinaryExpression {
         operator,
         left: Box::new(left),
@@ -183,16 +197,14 @@ fn parse_parenthesized_expression(lexer: &mut RustyLexer) -> Result<Statement, S
 }
 
 fn parse_unary_expression(lexer: &mut RustyLexer) -> Result<Statement, String> {
-    let current = 
-        match lexer.token {
-            Identifier => parse_reference(lexer),
-            LiteralNumber => parse_literal_number(lexer),
-            _ => Err(unexpected_token(lexer)),
-        };
-    
+    let current = match lexer.token {
+        Identifier => parse_reference(lexer),
+        LiteralNumber => parse_literal_number(lexer),
+        _ => Err(unexpected_token(lexer)),
+    };
     if current.is_ok() && lexer.token == KeywordAssignment {
         lexer.advance();
-        return Ok(Statement::Assignment{
+        return Ok(Statement::Assignment {
             left: Box::new(current?),
             right: Box::new(parse_primary_expression(lexer)?),
         });
@@ -250,6 +262,7 @@ fn parse_variable(
 mod tests {
     use super::super::lexer;
     use super::Statement;
+    use pretty_assertions::assert_eq;
 
     #[test]
     fn empty_returns_empty_compilation_unit() {
@@ -655,4 +668,150 @@ mod tests {
         }
     }
 
+    #[test]
+    fn equality_expression_test() {
+        let lexer = lexer::lex("PROGRAM exp x = 3; x - 0 <> 1 + 2; END_PROGRAM");
+        let result = super::parse(lexer).unwrap();
+
+        let prg = &result.units[0];
+        {
+            let statement = &prg.statements[0];
+            let ast_string = format!("{:#?}", statement);
+            let expected_ast = r#"BinaryExpression {
+    operator: Equal,
+    left: Reference {
+        name: "x",
+    },
+    right: LiteralNumber {
+        value: "3",
+    },
+}"#;
+            assert_eq!(ast_string, expected_ast);
+        }
+
+        {
+            let statement = &prg.statements[1];
+            let ast_string = format!("{:#?}", statement);
+            let expected_ast = r#"BinaryExpression {
+    operator: NotEqual,
+    left: BinaryExpression {
+        operator: Minus,
+        left: Reference {
+            name: "x",
+        },
+        right: LiteralNumber {
+            value: "0",
+        },
+    },
+    right: BinaryExpression {
+        operator: Plus,
+        left: LiteralNumber {
+            value: "1",
+        },
+        right: LiteralNumber {
+            value: "2",
+        },
+    },
+}"#;
+            assert_eq!(ast_string, expected_ast);
+        }
+    }
+    #[test]
+    fn comparison_expression_test() {
+        let lexer = lexer::lex(
+            "PROGRAM exp 
+                                    a < 3; 
+                                    b > 0;
+                                    c <= 7;
+                                    d >= 4;
+                                    e := 2 + 1 > 3 + 1;
+                                    END_PROGRAM",
+        );
+        let result = super::parse(lexer).unwrap();
+
+        let prg = &result.units[0];
+        {
+            let statement = &prg.statements[0];
+            let expected_ast = r#"BinaryExpression {
+    operator: Less,
+    left: Reference {
+        name: "a",
+    },
+    right: LiteralNumber {
+        value: "3",
+    },
+}"#;
+            assert_eq!(format!("{:#?}", statement), expected_ast);
+        }
+        {
+            let statement = &prg.statements[1]; // b > 0
+            let expected_ast = r#"BinaryExpression {
+    operator: Greater,
+    left: Reference {
+        name: "b",
+    },
+    right: LiteralNumber {
+        value: "0",
+    },
+}"#;
+            assert_eq!(format!("{:#?}", statement), expected_ast);
+        }
+        {
+            let statement = &prg.statements[2]; // c <= 7
+            let expected_ast = r#"BinaryExpression {
+    operator: LessOrEqual,
+    left: Reference {
+        name: "c",
+    },
+    right: LiteralNumber {
+        value: "7",
+    },
+}"#;
+            assert_eq!(format!("{:#?}", statement), expected_ast);
+        }
+        {
+            let statement = &prg.statements[3]; // d >= 4
+            let expected_ast = r#"BinaryExpression {
+    operator: GreaterOrEqual,
+    left: Reference {
+        name: "d",
+    },
+    right: LiteralNumber {
+        value: "4",
+    },
+}"#;
+            assert_eq!(format!("{:#?}", statement), expected_ast);
+        }
+        {
+            //e := 2 + 1 > 3 + 1;
+            let statement = &prg.statements[4];
+            let expected_ast = r#"Assignment {
+    left: Reference {
+        name: "e",
+    },
+    right: BinaryExpression {
+        operator: Greater,
+        left: BinaryExpression {
+            operator: Plus,
+            left: LiteralNumber {
+                value: "2",
+            },
+            right: LiteralNumber {
+                value: "1",
+            },
+        },
+        right: BinaryExpression {
+            operator: Plus,
+            left: LiteralNumber {
+                value: "3",
+            },
+            right: LiteralNumber {
+                value: "1",
+            },
+        },
+    },
+}"#;
+            assert_eq!(format!("{:#?}", statement), expected_ast);
+        }
+    }
 }