diff --git a/samtranslator/parser/parser.py b/samtranslator/parser/parser.py
index 9c0e0b13d..b060cc028 100644
--- a/samtranslator/parser/parser.py
+++ b/samtranslator/parser/parser.py
@@ -63,7 +63,7 @@ def _validate(self, sam_template, parameter_values):
             validation_errors = validator.validate(sam_template)
 
             if validation_errors:
-                LOG.warn("Template schema validation reported the following errors: " + ", ".join(validation_errors))
+                LOG.warning("Template schema validation reported the following errors: %s", validation_errors)
         except Exception as e:
             # Catching any exception and not re-raising to make sure any validation process won't break transform
             LOG.exception("Exception from SamTemplateValidator: %s", e)