diff --git a/cachalot/utils.py b/cachalot/utils.py
index 11017fd..5102aa2 100644
--- a/cachalot/utils.py
+++ b/cachalot/utils.py
@@ -77,7 +77,8 @@ def get_query_cache_key(compiler):
     """
     sql, params = compiler.as_sql()
     check_parameter_types(params)
-    cache_key = '%s:%s:%s' % (compiler.using, sql, [str(p) for p in params])
+    cache_key = '%s:%s:%s' % (compiler.using, sql,
+                              [text_type(p) for p in params])
     return sha1(cache_key.encode('utf-8')).hexdigest()