diff --git a/fsl/transform/flirt.py b/fsl/transform/flirt.py
index 97be2254a8dd2ef2ac72d7793090b87448993c9d..2fdc38b015a21fce527d897c76b1c99f6d5769d8 100644
--- a/fsl/transform/flirt.py
+++ b/fsl/transform/flirt.py
@@ -75,7 +75,7 @@ def fromFlirt(xform, src, ref, from_='voxel', to='world'):
 
 
 def toFlirt(xform, src, ref, from_='voxel', to='world'):
-    """Convert an affine affine matrix into a FLIRT matrix.
+    """Convert an affine matrix into a FLIRT matrix.
 
     :returns:   ``numpy`` array of shape ``(4, 4)`` containing a matrix
                 encoding a transformation from the source ``from_`` to