diff --git a/sql_server/pyodbc/base.py b/sql_server/pyodbc/base.py
index 7270a509..d50033e0 100644
--- a/sql_server/pyodbc/base.py
+++ b/sql_server/pyodbc/base.py
@@ -299,7 +299,7 @@ def format_params(self, params):
                 if self.driver_needs_utf8:
                     # FreeTDS (and other ODBC drivers?) doesn't support Unicode
                     # yet, so we need to encode parameters in utf-8
-                    fp.append(p.encode('utf-8'))
+                    fp.append(p)
                 else:
                     fp.append(p)
             elif isinstance(p, str):