diff --git a/Modules/FindOpenSSL.cmake b/Modules/FindOpenSSL.cmake
index bfbe01f59..3adc26926 100644
--- a/Modules/FindOpenSSL.cmake
+++ b/Modules/FindOpenSSL.cmake
@@ -285,7 +285,7 @@ endfunction()
 if (OPENSSL_INCLUDE_DIR)
   if(OPENSSL_INCLUDE_DIR AND EXISTS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h")
     file(STRINGS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h" openssl_version_str
-         REGEX "^#define[\t ]+OPENSSL_VERSION_NUMBER[\t ]+0x([0-9a-fA-F])+.*")
+         REGEX "^# *define[\t ]+OPENSSL_VERSION_NUMBER[\t ]+0x([0-9a-fA-F])+.*")
 
     # The version number is encoded as 0xMNNFFPPS: major minor fix patch status
     # The status gives if this is a developer or prerelease and is ignored here.