diff --git a/lib/galaxy/datatypes/tabular.py b/lib/galaxy/datatypes/tabular.py
index 3617ed5336a..c9161747af1 100644
--- a/lib/galaxy/datatypes/tabular.py
+++ b/lib/galaxy/datatypes/tabular.py
@@ -81,6 +81,7 @@ class TabularData( data.Text ):
             # For now, default to the old behavior, ugly as it is.  Remove this after adding 'matrix'.
             max_peek_size = 1000000  # 1 MB
             if os.stat( dataset.file_name ).st_size < max_peek_size:
+                self._clean_and_set_mime_type( trans, dataset.get_mime() )
                 return open( dataset.file_name )
             else:
                 trans.response.set_content_type( "text/html" )