diff --git a/nifty/operators/composed_operator/composed_operator.py b/nifty/operators/composed_operator/composed_operator.py
index d6b833e36c52015448c3c0a676219b279f000c38..d600cad26575db026b2b2854c0b6c9a29558f574 100644
--- a/nifty/operators/composed_operator/composed_operator.py
+++ b/nifty/operators/composed_operator/composed_operator.py
@@ -131,9 +131,6 @@ class ComposedOperator(LinearOperator):
     def _adjoint_inverse_times(self, x, spaces):
         return self._times_helper(x, spaces, func='adjoint_inverse_times')
 
-    def _inverse_adjoint_times(self, x, spaces):
-        return self._times_helper(x, spaces, func='inverse_adjoint_times')
-
     def _times_helper(self, x, spaces, func):
         space_index = 0
         if spaces is None:
diff --git a/nifty/operators/invertible_operator_mixin/invertible_operator_mixin.py b/nifty/operators/invertible_operator_mixin/invertible_operator_mixin.py
index 5aaff1097cf10aeeee14ca7232067ed783ff85cc..65c3f5f25dc5db140beb0efca919371c18932e39 100644
--- a/nifty/operators/invertible_operator_mixin/invertible_operator_mixin.py
+++ b/nifty/operators/invertible_operator_mixin/invertible_operator_mixin.py
@@ -103,8 +103,3 @@ class InvertibleOperatorMixin(object):
                                                 b=x,
                                                 x0=x0)
         return result
-
-    #MR FIXME: why? shouldn't this be equivalent to the adjoint inverse?
-    def _inverse_adjoint_times(self, x, spaces):
-        raise NotImplementedError(
-            "no generic instance method 'inverse_adjoint_times'.")
diff --git a/nifty/operators/linear_operator/linear_operator.py b/nifty/operators/linear_operator/linear_operator.py
index 64a0d0374cdeb9d4bf6209450134e35304f98da3..a1715435506f40bb02ec41eb613bfec975c2dfef 100644
--- a/nifty/operators/linear_operator/linear_operator.py
+++ b/nifty/operators/linear_operator/linear_operator.py
@@ -269,10 +269,6 @@ class LinearOperator(Loggable, object):
         raise NotImplementedError(
             "no generic instance method 'adjoint_inverse_times'.")
 
-    def _inverse_adjoint_times(self, x, spaces):
-        raise NotImplementedError(
-            "no generic instance method 'inverse_adjoint_times'.")
-
     def _check_input_compatibility(self, x, spaces, inverse=False):
         if not isinstance(x, Field):
             raise ValueError(