diff --git a/fs/path.py b/fs/path.py
index 875e536e..cf272032 100644
--- a/fs/path.py
+++ b/fs/path.py
@@ -437,7 +437,7 @@ def isbase(path1, path2):
     """
     _path1 = forcedir(abspath(path1))
     _path2 = forcedir(abspath(path2))
-    return _path1.startswith(_path2)
+    return _path2.startswith(_path1) # longer one is child
 
 
 def isparent(path1, path2):
diff --git a/tests/test_path.py b/tests/test_path.py
index af39541d..6b67d2a8 100644
--- a/tests/test_path.py
+++ b/tests/test_path.py
@@ -146,8 +146,8 @@ def test_recursepath(self):
         self.assertEquals(recursepath("", reverse=True), ["/"])
 
     def test_isbase(self):
-        self.assertTrue(isbase('foo/bar', 'foo'))
-        self.assertFalse(isbase('foo/bar', 'baz'))
+        self.assertTrue(isbase('foo', 'foo/bar'))
+        self.assertFalse(isbase('baz', 'foo/bar'))        
 
     def test_isparent(self):
         self.assertTrue(isparent("foo/bar", "foo/bar/spam.txt"))