diff --git a/pymongo/__init__.py b/pymongo/__init__.py
index 242b53b3a..d7298ad02 100644
--- a/pymongo/__init__.py
+++ b/pymongo/__init__.py
@@ -64,7 +64,7 @@ SLOW_ONLY = 1
 ALL = 2
 """Profile all operations."""
 
-version_tuple = (3, 9, 0)
+version_tuple = (3, 10, 0, '.dev0')
 
 def get_version_string():
     if isinstance(version_tuple[-1], str):
diff --git a/setup.py b/setup.py
index c0dd0d542..d116b02ec 100755
--- a/setup.py
+++ b/setup.py
@@ -39,7 +39,7 @@ except ImportError:
     except ImportError:
         _HAVE_SPHINX = False
 
-version = "3.9.0"
+version = "3.10.0.dev0"
 
 f = open("README.rst")
 try: