diff --git a/python/ycm/paths.py b/python/ycm/paths.py
index b5e1373d..e103778c 100644
--- a/python/ycm/paths.py
+++ b/python/ycm/paths.py
@@ -18,14 +18,16 @@
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import sys
 import vim
 import functools
+import re
 from ycmd import utils
 
 DIR_OF_CURRENT_SCRIPT = os.path.dirname( os.path.abspath( __file__ ) )
 
-WIN_PYTHON27_PATH = 'C:\python27\python.exe'
-WIN_PYTHON26_PATH = 'C:\python26\python.exe'
+WIN_PYTHON_PATH = os.path.join( sys.exec_prefix, 'python.exe' )
+PYTHON_BINARY_REGEX = re.compile( r'python(2(\.[67])?)?(.exe)?$' )
 
 
 def Memoize( obj ):
@@ -42,29 +44,56 @@ def Memoize( obj ):
 
 @Memoize
 def PathToPythonInterpreter():
-  user_path_to_python = vim.eval( 'g:ycm_path_to_python_interpreter' )
+  python_interpreter = vim.eval( 'g:ycm_path_to_python_interpreter' )
 
-  if user_path_to_python:
-    return user_path_to_python
+  if python_interpreter:
+    if IsPythonVersionCorrect( python_interpreter ):
+      return python_interpreter
 
-  # We check for 'python2' before 'python' because some OS's (I'm looking at
-  # you Arch Linux) have made the... interesting decision to point
-  # /usr/bin/python to python3.
-  python_names = [ 'python2', 'python' ]
+    raise RuntimeError( "Path in 'g:ycm_path_to_python_interpreter' option "
+                        "does not point to a valid Python 2.6 or 2.7." )
 
-  path_to_python = utils.PathToFirstExistingExecutable( python_names )
-  if path_to_python:
-    return path_to_python
+  # On UNIX platforms, we use sys.executable as the Python interpreter path.
+  # We cannot use sys.executable on Windows because for unknown reasons, it
+  # returns the Vim executable. Instead, we use sys.exec_prefix to deduce the
+  # interpreter path.
+  python_interpreter = ( WIN_PYTHON_PATH if utils.OnWindows() else
+                         sys.executable )
 
-  # On Windows, Python may not be on the PATH at all, so we check some common
-  # install locations.
-  if utils.OnWindows():
-    if os.path.exists( WIN_PYTHON27_PATH ):
-      return WIN_PYTHON27_PATH
-    elif os.path.exists( WIN_PYTHON26_PATH ):
-      return WIN_PYTHON26_PATH
+  if IsPythonVersionCorrect( python_interpreter ):
+    return python_interpreter
 
-  raise RuntimeError( 'Python 2.7/2.6 not installed!' )
+  # As a last resort, we search python in the PATH. We check 'python2' before
+  # 'python' because on some distributions (Arch Linux for example), python
+  # refers to python3.
+  python_interpreter = utils.PathToFirstExistingExecutable( [ 'python2',
+                                                              'python' ] )
+
+  if IsPythonVersionCorrect( python_interpreter ):
+    return python_interpreter
+
+  raise RuntimeError( "Cannot find Python 2.6 or 2.7. You can set its path "
+                      "using the 'g:ycm_path_to_python_interpreter' "
+                      "option." )
+
+
+def EndsWithPython( path ):
+  """Check if given path ends with a python 2.6 or 2.7 name."""
+  return PYTHON_BINARY_REGEX.search( path ) is not None
+
+
+def IsPythonVersionCorrect( path ):
+  """Check if given path is the Python interpreter version 2.6 or 2.7."""
+  if not EndsWithPython( path ):
+    return False
+
+  command = [ path,
+              '-c',
+              "import sys;"
+              "major, minor = sys.version_info[ :2 ];"
+              "sys.exit( major != 2 or minor < 6)" ]
+
+  return utils.SafePopen( command ).wait() == 0
 
 
 def PathToServerScript():
diff --git a/python/ycm/tests/paths_test.py b/python/ycm/tests/paths_test.py
new file mode 100644
index 00000000..d8e5ca7f
--- /dev/null
+++ b/python/ycm/tests/paths_test.py
@@ -0,0 +1,47 @@
+#
+# Copyright (C) 2016 YouCompleteMe contributors
+#
+# This file is part of YouCompleteMe.
+#
+# YouCompleteMe is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# YouCompleteMe is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
+
+from ycm.test_utils import MockVimModule
+MockVimModule()
+
+from nose.tools import ok_
+from ycm.paths import EndsWithPython
+
+
+def EndsWithPython_Python2Paths_test():
+  python_paths = [
+    'python',
+    '/usr/bin/python2.6',
+    '/home/user/.pyenv/shims/python2.7',
+    r'C:\Python26\python.exe'
+  ]
+
+  for path in python_paths:
+    ok_( EndsWithPython( path ) )
+
+
+def EndsWithPython_NotPython2Paths_test():
+  not_python_paths = [
+    '/opt/local/bin/vim',
+    r'C:\Program Files\Vim\vim74\gvim.exe',
+    '/usr/bin/python3',
+    '/home/user/.pyenv/shims/python3',
+  ]
+
+  for path in not_python_paths:
+    ok_( not EndsWithPython( path ) )