diff --git a/setup.py b/setup.py
index 20c2a22..f2b60a6 100644
--- a/setup.py
+++ b/setup.py
@@ -9,14 +9,46 @@
 # (C) 2001-2016 Chris Liechti <cliechti@gmx.net>
 #
 # SPDX-License-Identifier:    BSD-3-Clause
+import io
+import os
+import re
 
 try:
     from setuptools import setup
 except ImportError:
     from distutils.core import setup
 
-import serial
-version = serial.VERSION
+
+def read(*names, **kwargs):
+    """Python 2 and Python 3 compatible text file reading.
+
+    Required for single-sourcing the version string.
+    """
+    with io.open(
+        os.path.join(os.path.dirname(__file__), *names),
+        encoding=kwargs.get("encoding", "utf8")
+    ) as fp:
+        return fp.read()
+
+
+def find_version(*file_paths):
+    """
+    Search the file for a version string.
+
+    file_path contain string path components.
+
+    Reads the supplied Python module as text without importing it.
+    """
+    version_file = read(*file_paths)
+    version_match = re.search(r"^__version__ = ['\"]([^'\"]*)['\"]",
+                              version_file, re.M)
+    if version_match:
+        return version_match.group(1)
+    raise RuntimeError("Unable to find version string.")
+
+
+version = find_version('serial', '__init__.py')
+
 
 setup(
     name="pyserial",