diff --git a/src/main/java/io/proleap/cobol/preprocessor/sub/document/impl/CobolReplacementMapping.java b/src/main/java/io/proleap/cobol/preprocessor/sub/document/impl/CobolReplacementMapping.java
index 22ff577e9..547e81198 100644
--- a/src/main/java/io/proleap/cobol/preprocessor/sub/document/impl/CobolReplacementMapping.java
+++ b/src/main/java/io/proleap/cobol/preprocessor/sub/document/impl/CobolReplacementMapping.java
@@ -58,7 +58,7 @@ private String getRegexFromReplaceable(final String replaceable) {
 				regexParts[i] = Pattern.quote(part);
 			}
 
-			result = String.join(regexSeparator, regexParts);
+			result = "(?i)" + String.join(regexSeparator, regexParts);
 		}
 
 		return result;