diff --git a/nipype/interfaces/freesurfer/preprocess.py b/nipype/interfaces/freesurfer/preprocess.py
index 658b397630..2acd3fa0ff 100644
--- a/nipype/interfaces/freesurfer/preprocess.py
+++ b/nipype/interfaces/freesurfer/preprocess.py
@@ -1226,7 +1226,7 @@ def _list_outputs(self):
                 outputs['registered_file'] = op.abspath(_in.registered_file)
 
         if isdefined(_in.out_lta_file):
-            if isinstance(_in.out_fsl_file, bool):
+            if isinstance(_in.out_lta_file, bool):
                 suffix = '_bbreg_%s.lta' % _in.subject_id
                 out_lta_file = fname_presuffix(_in.source_file,
                                                suffix=suffix,