diff --git a/AUTHORS b/AUTHORS
index f1769116d..026c40fb7 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -82,6 +82,7 @@ Jason R. Coombs
 Javier Domingo Cansino
 Javier Romero
 Jeff Widman
+John Eddie Ayson
 John Towler
 Jon Sonesen
 Jonas Obrist
diff --git a/_pytest/doctest.py b/_pytest/doctest.py
index c1b6a81a8..6016265a5 100644
--- a/_pytest/doctest.py
+++ b/_pytest/doctest.py
@@ -59,8 +59,7 @@ def pytest_collect_file(path, parent):
 def _is_setup_py(config, path, parent):
     if path.basename != "setup.py":
         return False
-    with open(path.strpath, 'r') as f:
-        contents = f.read()
+    contents = path.read()
     return 'setuptools' in contents or 'distutils' in contents
 
 
diff --git a/changelog/502.feature b/changelog/502.feature
new file mode 100644
index 000000000..f768b650e
--- /dev/null
+++ b/changelog/502.feature
@@ -0,0 +1 @@
+Implement feature to skip valid setup.py files when ran with --doctest-modules
diff --git a/testing/test_doctest.py b/testing/test_doctest.py
index 8a81ea0ed..b8fa1fb77 100644
--- a/testing/test_doctest.py
+++ b/testing/test_doctest.py
@@ -561,6 +561,34 @@ class TestDoctests(object):
         reportinfo = items[0].reportinfo()
         assert reportinfo[1] == 1
 
+    def test_valid_setup_py(self, testdir):
+        '''
+        Test to make sure that pytest ignores valid setup.py files when ran
+        with --doctest-modules
+        '''
+        p = testdir.makepyfile(setup="""
+            from setuptools import setup, find_packages
+            setup(name='sample',
+                  version='0.0',
+                  description='description',
+                  packages=find_packages()
+            )
+        """)
+        result = testdir.runpytest(p, '--doctest-modules')
+        result.stdout.fnmatch_lines(['*collected 0 items*'])
+
+    def test_invalid_setup_py(self, testdir):
+        '''
+        Test to make sure that pytest reads setup.py files that are not used
+        for python packages when ran with --doctest-modules
+        '''
+        p = testdir.makepyfile(setup="""
+            def test_foo():
+                return 'bar'
+        """)
+        result = testdir.runpytest(p, '--doctest-modules')
+        result.stdout.fnmatch_lines(['*collected 1 item*'])
+
 
 class TestLiterals(object):