diff -r fe532dccf8f6 Lib/test/test_dbm_gnu.py
--- a/Lib/test/test_dbm_gnu.py	Mon Apr 14 10:30:43 2014 -0400
+++ b/Lib/test/test_dbm_gnu.py	Wed Apr 16 12:38:27 2014 -0500
@@ -93,5 +93,31 @@
         self.assertEqual(str(cm.exception),
                          "GDBM object has already been closed")
 
+    def test_bool_empty(self):
+        """Ensure bool(db with no entry) is False."""
+
+        self.g = gdbm.open(filename, 'c')
+        # Empty, should be False
+        self.assertFalse(bool(self.g))
+
+    def test_bool_not_empty(self):
+        """Ensure bool(db with an entry) is True."""
+
+        self.g = gdbm.open(filename, 'c')
+        self.g['a'] = 'b'
+        # Has an entry, should be True
+        self.assertTrue(bool(self.g))
+
+    def test_bool_on_closed_db_raises(self):
+        """Ensure bool(db) on closed db raises an error."""
+
+        self.g = gdbm.open(filename, 'c')
+        self.g['a'] = 'b'
+        self.g.close()
+
+        # After closing, bool(db) should raise
+        self.assertRaises(gdbm.error, bool, self.g)
+
+
 if __name__ == '__main__':
     unittest.main()
diff -r fe532dccf8f6 Lib/test/test_dbm_ndbm.py
--- a/Lib/test/test_dbm_ndbm.py	Mon Apr 14 10:30:43 2014 -0400
+++ b/Lib/test/test_dbm_ndbm.py	Wed Apr 16 12:38:27 2014 -0500
@@ -49,6 +49,31 @@
         self.assertEqual(str(cm.exception),
                          "DBM object has already been closed")
 
+    def test_bool_empty(self):
+        """Ensure bool(db with No entry) is False."""
+
+        with dbm.ndbm.open(self.filename, 'c') as db:
+            # Empty, should be False
+            self.assertFalse(bool(db))
+
+    def test_bool_not_empty(self):
+        """Ensure bool(db with an entry) is True."""
+
+        with dbm.ndbm.open(self.filename, 'c') as db:
+            db['a'] = 'b'
+            # Has an entry, should be True
+            self.assertTrue(bool(db))
+
+    def test_bool_on_closed_db_raises(self):
+        """Ensure bool(db) on closed db raises an error."""
+
+        with dbm.ndbm.open(self.filename, 'c') as db:
+            db['a'] = 'b'
+
+        # After closing, bool(db) should raise
+        self.assertRaises(dbm.ndbm.error, bool, db)
+
+
 
 if __name__ == '__main__':
     unittest.main()
diff -r fe532dccf8f6 Modules/_dbmmodule.c
--- a/Modules/_dbmmodule.c	Mon Apr 14 10:30:43 2014 -0400
+++ b/Modules/_dbmmodule.c	Wed Apr 16 12:38:27 2014 -0500
@@ -220,6 +220,27 @@
 }
 
 static int
+dbm_bool(dbmobject *dp)
+{
+    datum key;
+
+    if (dp->di_dbm == NULL) {
+        PyErr_SetString(DbmError, "DBM object has already been closed");
+        return -1;
+    }
+
+    if (dp->di_size > 0){
+        /* Known non-zero size. */
+        return 1;
+    }
+
+    /* Unknown size.  Ensure DBM object has an entry. */
+    key = dbm_firstkey(dp->di_dbm);
+    return 0 != key.dptr;
+}
+
+
+static int
 dbm_contains(PyObject *self, PyObject *arg)
 {
     dbmobject *dp = (dbmobject *)self;
@@ -396,6 +417,44 @@
     {NULL,              NULL}           /* sentinel */
 };
 
+
+static PyNumberMethods dbm_as_number = {
+    0,                  /*nb_add*/
+    0,                  /*nb_subtract*/
+    0,                  /*nb_multiply*/
+    0,                  /*nb_remainder*/
+    0,                  /*nb_divmod*/
+    0,                  /*nb_power*/
+    0,                  /*nb_negative*/
+    0,                  /*nb_positive*/
+    0,                  /*nb_absolute*/
+    (inquiry)dbm_bool,  /*nb_bool*/
+    0,                  /*nb_invert*/
+    0,                  /*nb_lshift*/
+    0,                  /*nb_rshift*/
+    0,                  /*nb_and*/
+    0,                  /*nb_xor*/
+    0,                  /*nb_or*/
+    0,                  /*nb_int*/
+    0,                  /*nb_reserved*/
+    0,                  /*nb_float*/
+    0,                  /* nb_inplace_add */
+    0,                  /* nb_inplace_subtract */
+    0,                  /* nb_inplace_multiply */
+    0,                  /* nb_inplace_remainder */
+    0,                  /* nb_inplace_power */
+    0,                  /* nb_inplace_lshift */
+    0,                  /* nb_inplace_rshift */
+    0,                  /* nb_inplace_and */
+    0,                  /* nb_inplace_xor */
+    0,                  /* nb_inplace_or */
+    0,                  /* nb_floor_divide */
+    0,                  /* nb_true_divide */
+    0,                  /* nb_inplace_floor_divide */
+    0,                  /* nb_inplace_true_divide */
+};
+
+
 static PyTypeObject Dbmtype = {
     PyVarObject_HEAD_INIT(NULL, 0)
     "_dbm.dbm",
@@ -407,7 +466,7 @@
     0,                            /*tp_setattr*/
     0,                            /*tp_reserved*/
     0,                            /*tp_repr*/
-    0,                            /*tp_as_number*/
+    &dbm_as_number,               /*tp_as_number*/
     &dbm_as_sequence,             /*tp_as_sequence*/
     &dbm_as_mapping,              /*tp_as_mapping*/
     0,                    /*tp_hash*/
diff -r fe532dccf8f6 Modules/_gdbmmodule.c
--- a/Modules/_gdbmmodule.c	Mon Apr 14 10:30:43 2014 -0400
+++ b/Modules/_gdbmmodule.c	Wed Apr 16 12:38:27 2014 -0500
@@ -286,6 +286,26 @@
 }
 
 static int
+dbm_bool(dbmobject *dp)
+{
+    datum key;
+
+    if (dp->di_dbm == NULL) {
+        PyErr_SetString(DbmError, "GDBM object has already been closed");
+        return -1;
+    }
+    
+    if (dp->di_size > 0){
+        /* Known non-zero size. */
+        return 1;
+    }
+
+    /* Unknown size.  Ensure DBM object has an entry. */
+    key = gdbm_firstkey(dp->di_dbm);
+    return 0 != key.dptr;
+}
+
+static int
 dbm_contains(PyObject *self, PyObject *arg)
 {
     dbmobject *dp = (dbmobject *)self;
@@ -453,6 +473,42 @@
     {NULL,              NULL}           /* sentinel */
 };
 
+static PyNumberMethods dbm_as_number = {
+    0,                  /*nb_add*/
+    0,                  /*nb_subtract*/
+    0,                  /*nb_multiply*/
+    0,                  /*nb_remainder*/
+    0,                  /*nb_divmod*/
+    0,                  /*nb_power*/
+    0,                  /*nb_negative*/
+    0,                  /*nb_positive*/
+    0,                  /*nb_absolute*/
+    (inquiry)dbm_bool,  /*nb_bool*/
+    0,                  /*nb_invert*/
+    0,                  /*nb_lshift*/
+    0,                  /*nb_rshift*/
+    0,                  /*nb_and*/
+    0,                  /*nb_xor*/
+    0,                  /*nb_or*/
+    0,                  /*nb_int*/
+    0,                  /*nb_reserved*/
+    0,                  /*nb_float*/
+    0,                  /* nb_inplace_add */
+    0,                  /* nb_inplace_subtract */
+    0,                  /* nb_inplace_multiply */
+    0,                  /* nb_inplace_remainder */
+    0,                  /* nb_inplace_power */
+    0,                  /* nb_inplace_lshift */
+    0,                  /* nb_inplace_rshift */
+    0,                  /* nb_inplace_and */
+    0,                  /* nb_inplace_xor */
+    0,                  /* nb_inplace_or */
+    0,                  /* nb_floor_divide */
+    0,                  /* nb_true_divide */
+    0,                  /* nb_inplace_floor_divide */
+    0,                  /* nb_inplace_true_divide */
+};
+
 static PyTypeObject Dbmtype = {
     PyVarObject_HEAD_INIT(0, 0)
     "_gdbm.gdbm",
@@ -464,7 +520,7 @@
     0,                                  /*tp_setattr*/
     0,                                  /*tp_reserved*/
     0,                                  /*tp_repr*/
-    0,                                  /*tp_as_number*/
+    &dbm_as_number,                     /*tp_as_number*/
     &dbm_as_sequence,                   /*tp_as_sequence*/
     &dbm_as_mapping,                    /*tp_as_mapping*/
     0,                                  /*tp_hash*/