diff --git a/doc/source/release.rst b/doc/source/release.rst
index 33e421fa55960..efde15bc23d3c 100644
--- a/doc/source/release.rst
+++ b/doc/source/release.rst
@@ -254,7 +254,8 @@ See :ref:`Internal Refactoring<whatsnew_0130.refactoring>`
 
   - ``swapaxes`` on a ``Panel`` with the same axes specified now return a copy
   - support attribute access for setting
-  - filter supports same api as original ``DataFrame`` filter
+  - ``filter`` supports same api as original ``DataFrame`` filter
+  - ``fillna`` refactored to ``core/generic.py``, while > 3ndim is ``NotImplemented``
 
 - Series now inherits from ``NDFrame`` rather than directly from ``ndarray``.
   There are several minor changes that affect the API.
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 36c3ff9085d87..4553e4804e98b 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -1569,6 +1569,18 @@ def fillna(self, value=None, method=None, axis=0, inplace=False,
 
                 return result
 
+            # > 3d
+            if self.ndim > 3:
+                raise NotImplementedError('cannot fillna with a method for > 3dims')
+
+            # 3d
+            elif self.ndim == 3:
+
+                # fill in 2d chunks
+                result = dict([ (col,s.fillna(method=method, value=value)) for col, s in compat.iteritems(self) ])
+                return self._constructor.from_dict(result)
+
+            # 2d or less
             method = com._clean_fill_method(method)
             new_data = self._data.interpolate(method=method,
                                               axis=axis,
diff --git a/pandas/core/panel.py b/pandas/core/panel.py
index 45101b1e2afd5..5f90eb9fa31a7 100644
--- a/pandas/core/panel.py
+++ b/pandas/core/panel.py
@@ -750,54 +750,6 @@ def _combine_panel(self, other, func):
 
         return self._constructor(result_values, items, major, minor)
 
-    def fillna(self, value=None, method=None):
-        """
-        Fill NaN values using the specified method.
-
-        Member Series / TimeSeries are filled separately.
-
-        Parameters
-        ----------
-        value : any kind (should be same type as array)
-            Value to use to fill holes (e.g. 0)
-
-        method : {'backfill', 'bfill', 'pad', 'ffill', None}, default 'pad'
-            Method to use for filling holes in reindexed Series
-
-            pad / ffill: propagate last valid observation forward to next valid
-            backfill / bfill: use NEXT valid observation to fill gap
-
-        Returns
-        -------
-        y : DataFrame
-
-        See also
-        --------
-        DataFrame.reindex, DataFrame.asfreq
-        """
-        if isinstance(value, (list, tuple)):
-            raise TypeError('"value" parameter must be a scalar or dict, but '
-                            'you passed a "{0}"'.format(type(value).__name__))
-        if value is None:
-            if method is None:
-                raise ValueError('must specify a fill method or value')
-            result = {}
-            for col, s in compat.iteritems(self):
-                result[col] = s.fillna(method=method, value=value)
-
-            return self._constructor.from_dict(result)
-        else:
-            if method is not None:
-                raise ValueError('cannot specify both a fill method and value')
-            new_data = self._data.fillna(value)
-            return self._constructor(new_data)
-
-    def ffill(self):
-        return self.fillna(method='ffill')
-
-    def bfill(self):
-        return self.fillna(method='bfill')
-
     def major_xs(self, key, copy=True):
         """
         Return slice of panel along major axis
diff --git a/pandas/tests/test_panel4d.py b/pandas/tests/test_panel4d.py
index 9b34631ecc894..4f7e75b401216 100644
--- a/pandas/tests/test_panel4d.py
+++ b/pandas/tests/test_panel4d.py
@@ -849,23 +849,11 @@ def test_sort_index(self):
         # assert_panel_equal(sorted_panel, self.panel)
 
     def test_fillna(self):
+        self.assert_(not np.isfinite(self.panel4d.values).all())
         filled = self.panel4d.fillna(0)
         self.assert_(np.isfinite(filled.values).all())
 
-        filled = self.panel4d.fillna(method='backfill')
-        assert_panel_equal(filled['l1'],
-                           self.panel4d['l1'].fillna(method='backfill'))
-
-        panel4d = self.panel4d.copy()
-        panel4d['str'] = 'foo'
-
-        filled = panel4d.fillna(method='backfill')
-        assert_panel_equal(filled['l1'],
-                           panel4d['l1'].fillna(method='backfill'))
-
-        empty = self.panel4d.reindex(labels=[])
-        filled = empty.fillna(0)
-        assert_panel4d_equal(filled, empty)
+        self.assertRaises(NotImplementedError, self.panel4d.fillna, method='pad')
 
     def test_swapaxes(self):
         result = self.panel4d.swapaxes('labels', 'items')