diff --git a/README.md b/README.md
index d572385..da681bc 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,8 @@ biol,lr3039
 pl,plj0001
 ```
 
+The input CSV cannot contain blank lines.
+
 # Output
 The output is stored in the `output.csv` CSV file.