diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index ba505fb5..edf6515b 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -260,10 +260,14 @@ class FloatField(BaseField):
         return value
 
     def validate(self, value):
-        if isinstance(value, int):
-            value = float(value)
+        if isinstance(value, (int, long)):
+            try:
+                value = float(value)
+            except OverflowError:
+                self.error('The value is too large to be converted to float')
+
         if not isinstance(value, float):
-            self.error('FloatField only accepts float values')
+            self.error('FloatField only accepts float, int and long values')
 
         if self.min_value is not None and value < self.min_value:
             self.error('Float value is too small')
diff --git a/tests/fields/fields.py b/tests/fields/fields.py
index 757f66a8..3b048094 100644
--- a/tests/fields/fields.py
+++ b/tests/fields/fields.py
@@ -399,20 +399,36 @@ class FieldTest(unittest.TestCase):
         class Person(Document):
             height = FloatField(min_value=0.1, max_value=3.5)
 
+        class BigPerson(Document):
+            height = FloatField()
+
         person = Person()
         person.height = 1.89
         person.validate()
 
         person.height = '2.0'
         self.assertRaises(ValidationError, person.validate)
+
         person.height = 0.01
         self.assertRaises(ValidationError, person.validate)
+
         person.height = 4.0
         self.assertRaises(ValidationError, person.validate)
 
         person_2 = Person(height='something invalid')
         self.assertRaises(ValidationError, person_2.validate)
 
+        big_person = BigPerson()
+
+        big_person.height = 1L
+        big_person.validate()
+
+        big_person.height = 2 ** 500
+        big_person.validate()
+
+        big_person.height = 2 ** 100000  # Too big for a float value
+        self.assertRaises(ValidationError, big_person.validate)
+
     def test_decimal_validation(self):
         """Ensure that invalid values cannot be assigned to decimal fields.
         """