diff --git a/src/interpreter/env.rs b/src/interpreter/env.rs
index fb20d5e..06c0407 100644
--- a/src/interpreter/env.rs
+++ b/src/interpreter/env.rs
@@ -1,4 +1,5 @@
 use futures_util::lock::Mutex;
+use solang_parser::pt::{Expression, Identifier};
 use std::{
     collections::{HashMap, HashSet},
     sync::Arc,
@@ -12,12 +13,12 @@ use alloy::{
     signers::{ledger::HDPath, local::PrivateKeySigner, Signature},
     transports::http::{Client, Http},
 };
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, bail, Result};
 use coins_ledger::{transports::LedgerAsync, Ledger};
 
 use crate::{interpreter::Config, vendor::ledger_signer::LedgerSigner};
 
-use super::{types::Type, Value};
+use super::{evaluate_expression, types::Type, Value};
 
 pub struct Env {
     variables: Vec<HashMap<String, Value>>,
@@ -173,6 +174,26 @@ impl Env {
         scope.insert(name.to_string(), value);
     }
 
+    pub async fn init_variable(
+        &mut self,
+        name: &Option<Identifier>,
+        type_: &Expression,
+        initializer: &Option<Expression>,
+    ) -> Result<()> {
+        let id = name.clone().ok_or(anyhow!("invalid declaration"))?.name;
+        let type_ = match evaluate_expression(self, Box::new(type_.clone())).await? {
+            Value::TypeObject(t) => t,
+            v => bail!("invalid type for variable, expected type, got {}", v),
+        };
+        let value = if let Some(e) = initializer {
+            evaluate_expression(self, Box::new(e.clone())).await?
+        } else {
+            type_.default_value()?
+        };
+        self.set_var(&id, value);
+        Ok(())
+    }
+
     fn set_wallet<S>(&mut self, signer: S) -> Result<()>
     where
         S: TxSigner<Signature> + Send + Sync + 'static,
diff --git a/src/interpreter/interpreter.rs b/src/interpreter/interpreter.rs
index 0d25060..f155e27 100644
--- a/src/interpreter/interpreter.rs
+++ b/src/interpreter/interpreter.rs
@@ -137,13 +137,8 @@ pub async fn evaluate_contract_part(
             env.set_var(&func.name, Value::Func(Function::UserDefined(func.clone())));
         }
         ContractPart::VariableDefinition(def) => {
-            let id = def.name.clone().ok_or(anyhow!("invalid declaration"))?.name;
-            if let Some(expr) = &def.initializer {
-                let result = evaluate_expression(env, Box::new(expr.clone())).await?;
-                env.set_var(&id, result.clone());
-            } else {
-                bail!("declarations need rhs")
-            }
+            env.init_variable(&def.name, &def.ty, &def.initializer)
+                .await?;
         }
         v => bail!("{} not supported", v),
     }
@@ -246,18 +241,8 @@ pub fn evaluate_statement(
             }
 
             Statement::VariableDefinition(_, var, expr) => {
-                let id = var
-                    .name
-                    .clone()
-                    .ok_or(anyhow!("invalid declaration {}", stmt))?
-                    .name;
-                if let Some(e) = expr {
-                    let result = evaluate_expression(env, Box::new(e.clone())).await?;
-                    env.set_var(&id, result.clone());
-                    Ok(StatementResult::Empty)
-                } else {
-                    bail!("declarations need rhs")
-                }
+                env.init_variable(&var.name, &var.ty, expr).await?;
+                Ok(StatementResult::Empty)
             }
             stmt => bail!("statement {:?} not supported", stmt),
         }
diff --git a/src/interpreter/types.rs b/src/interpreter/types.rs
index 60004f8..5800c12 100644
--- a/src/interpreter/types.rs
+++ b/src/interpreter/types.rs
@@ -253,6 +253,36 @@ impl TryFrom<Type> for DynSolType {
 }
 
 impl Type {
+    pub fn default_value(&self) -> Result<Value> {
+        let value = match self {
+            Type::Null => Value::Null,
+            Type::Address => Value::Addr(Address::ZERO),
+            Type::Bool => Value::Bool(false),
+            Type::Int(size) => Value::Int(I256::ZERO, *size),
+            Type::Uint(size) => Value::Uint(U256::ZERO, *size),
+            Type::FixBytes(size) => Value::FixBytes(B256::default(), *size),
+            Type::Bytes => Value::Bytes(vec![]),
+            Type::String => Value::Str("".to_string()),
+            Type::Array(_) => Value::Array(vec![]),
+            Type::FixedArray(t, size) => Value::Array(vec![t.default_value()?; *size]),
+            Type::NamedTuple(_, fields) => Value::NamedTuple(
+                "".to_string(),
+                fields
+                    .iter()
+                    .map(|(k, v)| v.default_value().map(|v_| (k.clone(), v_)))
+                    .collect::<Result<IndexMap<_, _>>>()?,
+            ),
+            Type::Tuple(types) => Value::Array(
+                types
+                    .iter()
+                    .map(|t| t.default_value())
+                    .collect::<Result<Vec<_>>>()?,
+            ),
+            _ => bail!("cannot get default value for type {}", self),
+        };
+        Ok(value)
+    }
+
     pub fn is_int(&self) -> bool {
         matches!(self, Type::Int(_) | Type::Uint(_))
     }