diff --git a/django/contrib/gis/db/models/sql/conversion.py b/django/contrib/gis/db/models/sql/conversion.py
index afc1053790d..acc277ed624 100644
--- a/django/contrib/gis/db/models/sql/conversion.py
+++ b/django/contrib/gis/db/models/sql/conversion.py
@@ -4,6 +4,8 @@ database.
 """
 from __future__ import unicode_literals
 
+from decimal import Decimal
+
 from django.contrib.gis.db.models.fields import GeoSelectFormatMixin
 from django.contrib.gis.geometry.backend import Geometry
 from django.contrib.gis.measure import Area, Distance
@@ -27,6 +29,10 @@ class AreaField(BaseField):
     def from_db_value(self, value, expression, connection, context):
         if connection.features.interprets_empty_strings_as_nulls and value == '':
             value = None
+        # If the database returns a Decimal, convert it to a float as expected
+        # by the Python geometric objects.
+        if isinstance(value, Decimal):
+            value = float(value)
         # If the units are known, convert value into area measure.
         if value is not None and self.area_att:
             value = Area(**{self.area_att: value})
diff --git a/docs/releases/1.10.txt b/docs/releases/1.10.txt
index 0e7381a9728..fd2b1a5d40c 100644
--- a/docs/releases/1.10.txt
+++ b/docs/releases/1.10.txt
@@ -353,7 +353,10 @@ Backwards incompatible changes in 1.10
 Database backend API
 --------------------
 
-* ...
+* GIS's ``AreaField`` uses an unspecified underlying numeric type that could in
+  practice be any numeric Python type. ``decimal.Decimal`` values retrieved
+  from the database are now converted to ``float`` to make it easier to combine
+  them with values used by the GIS libraries.
 
 ``select_related()`` prohibits non-relational fields for nested relations
 -------------------------------------------------------------------------
@@ -515,6 +518,10 @@ Miscellaneous
   argument of the ``render_options()`` method is also removed, making
   ``selected_choices`` the first argument.
 
+* On Oracle/GIS, the :class:`~django.contrib.gis.db.models.functions.Area`
+  aggregate function now returns a ``float`` instead of ``decimal.Decimal``.
+  (It's still wrapped in a measure of square meters.)
+
 .. _deprecated-features-1.10:
 
 Features deprecated in 1.10
diff --git a/tests/gis_tests/geoapp/test_functions.py b/tests/gis_tests/geoapp/test_functions.py
index aeb1007c565..344fa03e61d 100644
--- a/tests/gis_tests/geoapp/test_functions.py
+++ b/tests/gis_tests/geoapp/test_functions.py
@@ -240,7 +240,9 @@ class GISFunctionsTests(TestCase):
             CountryWebMercator.objects.create(name=c.name, mpoly=c.mpoly)
         # Test in projected coordinate system
         qs = CountryWebMercator.objects.annotate(area_sum=Sum(functions.Area('mpoly')))
-        for c in qs:
+        # Some backends (e.g. Oracle) cannot group by multipolygon values, so
+        # defer such fields in the aggregation query.
+        for c in qs.defer('mpoly'):
             result = c.area_sum
             # If the result is a measure object, get value.
             if isinstance(result, Area):