diff --git a/nested_query_string/nested_query_string.py b/nested_query_string/nested_query_string.py
index 5b50a2f..51faf8f 100644
--- a/nested_query_string/nested_query_string.py
+++ b/nested_query_string/nested_query_string.py
@@ -33,8 +33,8 @@ def encode(cls, value, key = None):
       return result
     elif class_name == list:
       result = []
-      for v in value:
-        result.append(cls.encode(v, key+'[]'))
+      for i, v in enumerate(value):
+        result.append(cls.encode(v, key+'[{0}]'.format(i)))
       result = '&'.join(result)
       return result
     elif class_name == str: