diff --git a/pymongo/database.py b/pymongo/database.py
index e81193093..3aa726367 100644
--- a/pymongo/database.py
+++ b/pymongo/database.py
@@ -15,7 +15,9 @@
 """Database level operations."""
 
 import types
+import md5
 
+from son import SON
 from son_manipulator import ObjectIdInjector
 from collection import Collection
 from errors import InvalidName, CollectionInvalid, OperationFailure
@@ -274,3 +276,55 @@ class Database(object):
 
     def next(self):
         raise TypeError("'Database' object is not iterable")
+
+    # TODO this should probably be private, but I'm using it for some tests right now...
+    def _password_digest(self, password):
+        """Get a password digest to use for authentication, given a password
+        """
+        if not isinstance(password, types.StringTypes):
+            raise TypeError("password must be an instance of (str, unicode)")
+
+        return unicode(md5.new("mongo" + password).hexdigest())
+
+    def authenticate(self, name, password):
+        """Authenticate to use this database.
+
+        Once authenticated, the user has full read and write access to this
+        database. Raises TypeError if either name or password is not an instance
+        of (str, unicode). Authentication lasts for the life of the database
+        connection, or until `Database.logout` is called.
+
+        The "admin" database is special. Authenticating on "admin" gives access
+        to *all* databases. Effectively, "admin" access means root access to the
+        database.
+
+        Arguments:
+        - `name`: the name of the user to authenticate
+        - `password`: the password of the user to authenticate
+        """
+        if not isinstance(name, types.StringTypes):
+            raise TypeError("name must be an instance of (str, unicode)")
+        if not isinstance(password, types.StringTypes):
+            raise TypeError("password must be an instance of (str, unicode)")
+
+        nonce = self._command({"getnonce": 1})
+        if nonce["ok"] != 1:
+            raise OperationFailure("failed to get nonce: %s" % result["errmsg"])
+        nonce = nonce["nonce"]
+        result = self._command(SON([("authenticate", 1),
+                                    ("user", unicode(name)),
+                                    ("nonce", nonce),
+                                    ("key", unicode(md5.new("%s%s%s" % (nonce,
+                                                                        unicode(name),
+                                                                        self._password_digest(password)
+                                                                        )).hexdigest()))]))
+        return result["ok"] == 1
+
+    def logout(self):
+        """Deauthorize use of this database for this connection.
+
+        Note that other databases may still be authorized.
+        """
+        result = self._command({"logout": 1})
+        if result["ok"] != 1:
+            raise OperationFailure("logout failed: %s" % result["errmsg"])
diff --git a/test/test_database.py b/test/test_database.py
index 0bb5374cd..ab1024f39 100644
--- a/test/test_database.py
+++ b/test/test_database.py
@@ -190,6 +190,34 @@ class TestDatabase(unittest.TestCase):
         self.assertEqual(None, db.error())
         self.assertEqual(None, db.previous_error())
 
+    def test_password_digest(self):
+        db = self.connection.test
+
+        self.assertRaises(TypeError, db._password_digest, 5)
+        self.assertRaises(TypeError, db._password_digest, True)
+        self.assertRaises(TypeError, db._password_digest, None)
+
+        self.assertTrue(isinstance(db._password_digest("password"), types.UnicodeType))
+        self.assertEqual(db._password_digest("password"), u"3b483f665f97e2fdf97575e72321fc5b")
+        self.assertEqual(db._password_digest("password"), db._password_digest(u"password"))
+
+    def test_authenticate(self):
+        db = self.connection.test
+        db.system.users.remove({})
+        db.system.users.insert({"user": u"mike", "pwd": db._password_digest("password")})
+
+        self.assertRaises(TypeError, db.authenticate, 5, "password")
+        self.assertRaises(TypeError, db.authenticate, "mike", 5)
+
+        self.assertFalse(db.authenticate("mike", "not a real password"))
+        self.assertFalse(db.authenticate("faker", "password"))
+        self.assertTrue(db.authenticate("mike", "password"))
+        self.assertTrue(db.authenticate(u"mike", u"password"))
+
+        # just make sure there are no exceptions here
+        db.logout()
+        db.logout()
+
     # TODO some of these tests belong in the collection level testing.
     def test_save_find_one(self):
         db = Database(self.connection, "test")