diff -r 31a05787eb93 Lib/site.py
--- a/Lib/site.py	Fri Jan 20 10:39:13 2017 -0500
+++ b/Lib/site.py	Fri Jan 20 20:46:30 2017 -0500
@@ -163,6 +163,8 @@
         for n, line in enumerate(f):
             if line.startswith("#"):
                 continue
+            if line.strip() == "":
+                continue
             try:
                 if line.startswith(("import ", "import\t")):
                     exec(line)
diff -r 31a05787eb93 Lib/test/test_site.py
--- a/Lib/test/test_site.py	Fri Jan 20 10:39:13 2017 -0500
+++ b/Lib/test/test_site.py	Fri Jan 20 20:46:30 2017 -0500
@@ -153,6 +153,12 @@
         self.assertRegex(err_out.getvalue(), 'Traceback')
         self.assertRegex(err_out.getvalue(), 'ValueError')
 
+    def test_addpackage_empty_lines(self):
+        # Issue 29326
+        pth_dir, pth_fn = self.make_pth("\n\n  \n\n")
+        known_paths = site.addpackage(pth_dir, pth_fn, set())
+        self.assertEqual(len(known_paths), 0)
+
     def test_addsitedir(self):
         # Same tests for test_addpackage since addsitedir() essentially just
         # calls addpackage() for every .pth file in the directory