diff --git a/nipype/interfaces/fsl/epi.py b/nipype/interfaces/fsl/epi.py
index 0b8dfff37b..7d2784196b 100644
--- a/nipype/interfaces/fsl/epi.py
+++ b/nipype/interfaces/fsl/epi.py
@@ -568,8 +568,8 @@ class EpiRegInputSpec(FSLCommandInputSpec):
                    position=-3, desc='wholehead T1 image')
     t1_brain = File(exists=True, argstr='--t1brain=%s', mandatory=True,
                     position=-2, desc='brain extracted T1 image')
-    out_base = traits.String(desc='output base name', argstr='--out=%s',
-                             position=-1)
+    out_base = traits.String("epi2struct", desc='output base name', argstr='--out=%s',
+                             position=-1, usedefault=True)
     fmap = File(exists=True, argstr='--fmap=%s',
                 desc='fieldmap image (in rad/s)')
     fmapmag = File(exists=True, argstr='--fmapmag=%s',
diff --git a/nipype/interfaces/fsl/tests/test_auto_EpiReg.py b/nipype/interfaces/fsl/tests/test_auto_EpiReg.py
index 113b886599..8160f4cd35 100644
--- a/nipype/interfaces/fsl/tests/test_auto_EpiReg.py
+++ b/nipype/interfaces/fsl/tests/test_auto_EpiReg.py
@@ -29,6 +29,7 @@ def test_EpiReg_inputs():
     ),
     out_base=dict(argstr='--out=%s',
     position=-1,
+    usedefault=True,
     ),
     output_type=dict(),
     pedir=dict(argstr='--pedir=%s',