diff --git a/transmute_core/param_extractor.py b/transmute_core/param_extractor.py
index 96e40a8..ca1e3c7 100644
--- a/transmute_core/param_extractor.py
+++ b/transmute_core/param_extractor.py
@@ -36,6 +36,8 @@ def extract_params(self, context, transmute_func, content_type):
             if values is NoArgument:
                 empty_args.append(arginfo)
             else:
+                if is_list and len(values) == 0:
+                    values = values[0].split(",")
                 args[name] = context.serializers.load(arginfo.type, values)
 
         for name, param in parameters.header.items():