diff --git a/gensim/models/ldamodel.py b/gensim/models/ldamodel.py
index 048e5d4c51..c2324904e3 100755
--- a/gensim/models/ldamodel.py
+++ b/gensim/models/ldamodel.py
@@ -34,6 +34,7 @@
 import logging
 import numpy as np  # for arrays, array broadcasting etc.
 import numbers
+import os
 
 from gensim import interfaces, utils, matutils
 from gensim.models import basemodel
@@ -239,11 +240,11 @@ def __init__(self, corpus=None, num_topics=100, id2word=None,
         prior directly from your data.
 
         `eta` can be a scalar for a symmetric prior over topic/word
-        distributions, or a vector of shape num_words, which can be used to 
-        impose (user defined) asymmetric priors over the word distribution. 
+        distributions, or a vector of shape num_words, which can be used to
+        impose (user defined) asymmetric priors over the word distribution.
         It also supports the special value 'auto', which learns an asymmetric
         prior over words directly from your data. `eta` can also be a matrix
-        of shape num_topics x num_words, which can be used to impose 
+        of shape num_topics x num_words, which can be used to impose
         asymmetric priors over the word distribution on a per-topic basis
         (can not be learned from data).
 
@@ -995,7 +996,7 @@ def __getitem__(self, bow, eps=None):
         """
         return self.get_document_topics(bow, eps, self.minimum_phi_value, self.per_word_topics)
 
-    def save(self, fname, ignore=['state', 'dispatcher'], *args, **kwargs):
+    def save(self, fname, ignore=['state', 'dispatcher'], separately=None, *args, **kwargs):
         """
         Save the model to file.
 
@@ -1024,18 +1025,39 @@ def save(self, fname, ignore=['state', 'dispatcher'], *args, **kwargs):
         """
         if self.state is not None:
             self.state.save(utils.smart_extension(fname, '.state'), *args, **kwargs)
+        # Save the dictionary separately if not in 'ignore'.
+        if 'id2word' not in ignore:
+            utils.pickle(self.id2word, utils.smart_extension(fname, '.id2word'))
 
-        # make sure 'state' and 'dispatcher' are ignored from the pickled object, even if
+        # make sure 'state', 'id2word' and 'dispatcher' are ignored from the pickled object, even if 
         # someone sets the ignore list themselves
         if ignore is not None and ignore:
             if isinstance(ignore, six.string_types):
                 ignore = [ignore]
             ignore = [e for e in ignore if e] # make sure None and '' are not in the list
-            ignore = list(set(['state', 'dispatcher']) | set(ignore))
+            ignore = list(set(['state', 'dispatcher', 'id2word']) | set(ignore))
         else:
-            ignore = ['state', 'dispatcher']
-        super(LdaModel, self).save(fname, *args, ignore=ignore, **kwargs)
-
+            ignore = ['state', 'dispatcher', 'id2word']
+        
+        # make sure 'expElogbeta' and 'sstats' are ignored from the pickled object, even if
+        # someone sets the separately list themselves.
+        separately_explicit = ['expElogbeta', 'sstats']
+        # Also add 'alpha' and 'eta' to separately list if they are set 'auto' or some
+        # array manually.
+        if (isinstance(self.alpha, six.string_types) and self.alpha == 'auto') or len(self.alpha.shape) != 1:
+            separately_explicit.append('alpha')
+        if (isinstance(self.eta, six.string_types) and self.eta == 'auto') or len(self.eta.shape) != 1:
+            separately_explicit.append('eta')
+        # Merge separately_explicit with separately.
+        if separately:
+            if isinstance(separately, six.string_types):
+                separately = [separately]
+            separately = [e for e in separately if e] # make sure None and '' are not in the list
+            separately = list(set(separately_explicit) | set(separately))
+        else:
+            separately = separately_explicit
+        super(LdaModel, self).save(fname, ignore=ignore, separately = separately, *args, **kwargs)
+       
     @classmethod
     def load(cls, fname, *args, **kwargs):
         """
@@ -1053,5 +1075,13 @@ def load(cls, fname, *args, **kwargs):
             result.state = super(LdaModel, cls).load(state_fname, *args, **kwargs)
         except Exception as e:
             logging.warning("failed to load state from %s: %s", state_fname, e)
+        id2word_fname = utils.smart_extension(fname, '.id2word')
+        if (os.path.isfile(id2word_fname)):
+            try:
+                result.id2word = utils.unpickle(id2word_fname)
+            except Exception as e:
+                logging.warning("failed to load id2word dictionary from %s: %s", id2word_fname, e)
+        else:
+            result.id2word = None
         return result
 # endclass LdaModel
diff --git a/gensim/test/test_data/ldamodel_python_2_7 b/gensim/test/test_data/ldamodel_python_2_7
new file mode 100644
index 0000000000..f8ee3514e1
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diff --git a/gensim/test/test_data/ldamodel_python_2_7.expElogbeta.npy b/gensim/test/test_data/ldamodel_python_2_7.expElogbeta.npy
new file mode 100644
index 0000000000..1971e44b14
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diff --git a/gensim/test/test_data/ldamodel_python_2_7.id2word b/gensim/test/test_data/ldamodel_python_2_7.id2word
new file mode 100644
index 0000000000..5fad7912fb
Binary files /dev/null and b/gensim/test/test_data/ldamodel_python_2_7.id2word differ
diff --git a/gensim/test/test_data/ldamodel_python_2_7.state b/gensim/test/test_data/ldamodel_python_2_7.state
new file mode 100644
index 0000000000..424cf0096d
Binary files /dev/null and b/gensim/test/test_data/ldamodel_python_2_7.state differ
diff --git a/gensim/test/test_data/ldamodel_python_3_5 b/gensim/test/test_data/ldamodel_python_3_5
new file mode 100644
index 0000000000..0733b35fd5
Binary files /dev/null and b/gensim/test/test_data/ldamodel_python_3_5 differ
diff --git a/gensim/test/test_data/ldamodel_python_3_5.expElogbeta.npy b/gensim/test/test_data/ldamodel_python_3_5.expElogbeta.npy
new file mode 100644
index 0000000000..1971e44b14
Binary files /dev/null and b/gensim/test/test_data/ldamodel_python_3_5.expElogbeta.npy differ
diff --git a/gensim/test/test_data/ldamodel_python_3_5.id2word b/gensim/test/test_data/ldamodel_python_3_5.id2word
new file mode 100644
index 0000000000..8c8a2b7af0
Binary files /dev/null and b/gensim/test/test_data/ldamodel_python_3_5.id2word differ
diff --git a/gensim/test/test_data/ldamodel_python_3_5.state b/gensim/test/test_data/ldamodel_python_3_5.state
new file mode 100644
index 0000000000..62d7635c32
Binary files /dev/null and b/gensim/test/test_data/ldamodel_python_3_5.state differ
diff --git a/gensim/test/test_ldamodel.py b/gensim/test/test_ldamodel.py
index 7f1b4ba44e..041724dad2 100644
--- a/gensim/test/test_ldamodel.py
+++ b/gensim/test/test_ldamodel.py
@@ -44,9 +44,10 @@
 corpus = [dictionary.doc2bow(text) for text in texts]
 
 
-def testfile():
+def testfile(test_fname=''):
     # temporary data will be stored to this file
-    return os.path.join(tempfile.gettempdir(), 'gensim_models.tst')
+    fname = 'gensim_models_' + test_fname + '.tst' 
+    return os.path.join(tempfile.gettempdir(), fname)
 
 
 def testRandomState():
@@ -61,6 +62,7 @@ def setUp(self):
         self.class_ = ldamodel.LdaModel
         self.model = self.class_(corpus, id2word=dictionary, num_topics=2, passes=100)
 
+
     def testTransform(self):
         passed = False
         # sometimes, LDA training gets stuck at a local minimum
@@ -408,8 +410,22 @@ def testPersistence(self):
         tstvec = []
         self.assertTrue(np.allclose(model[tstvec], model2[tstvec])) # try projecting an empty vector
 
+    def testModelCompatibilityWithPythonVersions(self):
+        fname_model_2_7 = datapath('ldamodel_python_2_7')
+        model_2_7 = self.class_.load(fname_model_2_7)
+        fname_model_3_5 = datapath('ldamodel_python_3_5')
+        model_3_5 = self.class_.load(fname_model_3_5)
+        self.assertEqual(model_2_7.num_topics, model_3_5.num_topics)
+        self.assertTrue(np.allclose(model_2_7.expElogbeta, model_3_5.expElogbeta))
+        tstvec = []
+        self.assertTrue(np.allclose(model_2_7[tstvec], model_3_5[tstvec])) # try projecting an empty vector
+        id2word_2_7 = dict((k,v) for k,v in model_2_7.id2word.iteritems())
+        id2word_3_5 = dict((k,v) for k,v in model_3_5.id2word.iteritems())
+        self.assertEqual(set(id2word_2_7.keys()), set(id2word_3_5.keys()))
+
+
     def testPersistenceIgnore(self):
-        fname = testfile()
+        fname = testfile('testPersistenceIgnore')
         model = ldamodel.LdaModel(self.corpus, num_topics=2)
         model.save(fname, ignore='id2word')
         model2 = ldamodel.LdaModel.load(fname)
diff --git a/gensim/utils.py b/gensim/utils.py
index 5db16a92e5..907e1e657f 100644
--- a/gensim/utils.py
+++ b/gensim/utils.py
@@ -906,10 +906,12 @@ def pickle(obj, fname, protocol=2):
 
 def unpickle(fname):
     """Load pickled object from `fname`"""
-    with smart_open(fname) as f:
+    with smart_open(fname, 'rb') as f:
         # Because of loading from S3 load can't be used (missing readline in smart_open)
-        return _pickle.loads(f.read())
-
+        if sys.version_info > (3, 0):
+            return _pickle.load(f, encoding='latin1')
+        else:
+            return _pickle.loads(f.read())
 
 def revdict(d):
     """