diff --git a/src/main/java/com/persiantools4j/nationalid/NationalIdServiceImpl.java b/src/main/java/com/persiantools4j/nationalid/NationalIdServiceImpl.java
index fbbf5a5..de30747 100644
--- a/src/main/java/com/persiantools4j/nationalid/NationalIdServiceImpl.java
+++ b/src/main/java/com/persiantools4j/nationalid/NationalIdServiceImpl.java
@@ -113,7 +113,6 @@ private void validateNationalIdFormat(String nationalId) {
         if (nationalId == null) {
             throw new ValidationException("National ID is null");
         }
-        nationalId = nationalId.trim();
         if (!nationalId.matches("\\d{10}") || nationalId.matches("(\\d)\\1{9}")) {
             throw new ValidationException("Invalid National ID format: " + nationalId);
         }