diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 85b2acb9d2..5681311a65 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -54,7 +54,7 @@ class UnicodeCursorWrapper(object):
 
     def execute(self, sql, params=()):
         try:
-            return self.cursor.execute(sql, params)
+            return self.cursor.execute(smart_str(sql, self.charset), self.format_params(params))
         except Database.IntegrityError, e:
             raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
         except Database.DatabaseError, e: