diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index 157c40e8325..09d13c417cb 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -732,8 +732,8 @@ class DecimalField(Field):
         return util.format_number(value, self.max_digits, self.decimal_places)
 
     def get_db_prep_value(self, value):
-        return connection.ops.value_to_db_decimal(value, self.max_digits,
-                                                  self.decimal_places)
+        return connection.ops.value_to_db_decimal(self.to_python(value),
+                self.max_digits, self.decimal_places)
 
     def get_manipulator_field_objs(self):
         return [curry(oldforms.DecimalField, max_digits=self.max_digits, decimal_places=self.decimal_places)]
diff --git a/tests/regressiontests/model_fields/models.py b/tests/regressiontests/model_fields/models.py
index 790bc5010ed..455e2b3ded0 100644
--- a/tests/regressiontests/model_fields/models.py
+++ b/tests/regressiontests/model_fields/models.py
@@ -1,8 +1,14 @@
 
 from django.db import models
 
+try:
+    import decimal
+except ImportError:
+    from django.utils import _decimal as decimal    # Python 2.3 fallback
+
 class Foo(models.Model):
     a = models.CharField(max_length=10)
+    d = models.DecimalField(max_digits=5, decimal_places=3)
 
 def get_foo():
     return Foo.objects.get(id=1)
@@ -22,14 +28,14 @@ class Whiz(models.Model):
                 (3,'Third'),
                 (4,'Fourth'),
             )
-        ),        
+        ),
         (0,'Other'),
     )
     c = models.IntegerField(choices=CHOICES, null=True)
-    
+
 __test__ = {'API_TESTS':"""
 # Create a couple of Places.
->>> f = Foo.objects.create(a='abc')
+>>> f = Foo.objects.create(a='abc', d=decimal.Decimal("12.34"))
 >>> f.id
 1
 >>> b = Bar(b = "bcd")
@@ -67,5 +73,10 @@ None
 >>> w.get_c_display()
 u''
 
+# Regression test for #8023: should be able to filter decimal fields using
+# strings (which is what gets passed through from, e.g., the admin interface).
+>>> Foo.objects.filter(d=u'1.23')
+[]
+
 
 """}