diff --git a/tools/toolchains/iar.py b/tools/toolchains/iar.py
index b54487869a..ecfd6c8de5 100644
--- a/tools/toolchains/iar.py
+++ b/tools/toolchains/iar.py
@@ -167,7 +167,7 @@ class IAR(mbedToolchain):
         opts = ['-D%s' % d for d in defines]
         if for_asm:
             config_macros = self.config.get_config_data_macros()
-            macros_cmd = ['"-D%s"' % d.replace('"', '').replace('//','/\/') for d in config_macros]
+            macros_cmd = ['"-D%s"' % d for d in config_macros if not '"' in d]
             if self.RESPONSE_FILES:
                 via_file = self.make_option_file(
                     macros_cmd, "asm_macros_{}.xcl")