diff --git a/compute_mappability.R b/compute_mappability.R
index 4165fe6..139ebaa 100644
--- a/compute_mappability.R
+++ b/compute_mappability.R
@@ -4,7 +4,6 @@
 ### took an weighted average of both mappabilities. weights are proportional to lengths.
 
 suppressMessages(library(data.table))
-suppressMessages(library(stringr))
 suppressMessages(library(intervals))
 suppressMessages(library(stats))
 suppressMessages(library(argparser))
diff --git a/prerequisites.md b/prerequisites.md
index a7fcf42..122d4de 100644
--- a/prerequisites.md
+++ b/prerequisites.md
@@ -61,7 +61,7 @@ Bowtie index files are required to align k-mers to the genome. You may either do
 - Linux
 - R
   - Please make sure the path variable includes the location for `Rscript`.
-  - Please make sure the following R packages are installed: data.table, stringr, intervals, argparser, stats, 
+  - Please make sure the following R packages are installed: data.table, intervals, argparser, stats, 
 - bowtie v1
   - Please make sure the path variable includes the location for `bowtie`.