diff --git a/nmt/model.py b/nmt/model.py
index e0c4f4e03..b7e79ca03 100644
--- a/nmt/model.py
+++ b/nmt/model.py
@@ -362,7 +362,7 @@ def build_graph(self, hparams, scope=None):
         sample_id: sampling indices.
 
     Raises:
-      ValueError: if encoder_type differs from mono and bi, or
+      ValueError: if encoder_type differs from uni and bi, or
         attention_option is not (luong | scaled_luong |
         bahdanau | normed_bahdanau).
     """