diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index d90f0cc225..9d0967fa2b 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -278,7 +278,7 @@ def typecast_string(s):
     """
     Cast all returned strings to unicode strings.
     """
-    if not s:
+    if not s and not isinstance(s, str):
         return s
     return smart_unicode(s)
 
diff --git a/tests/regressiontests/model_regress/models.py b/tests/regressiontests/model_regress/models.py
index 0fee831212..7aa9e2a7c4 100644
--- a/tests/regressiontests/model_regress/models.py
+++ b/tests/regressiontests/model_regress/models.py
@@ -10,6 +10,7 @@ class Article(models.Model):
     headline = models.CharField(max_length=100, default='Default headline')
     pub_date = models.DateTimeField()
     status = models.IntegerField(blank=True, null=True, choices=CHOICES)
+    misc_data = models.CharField(max_length=100, blank=True)
 
     class Meta:
         ordering = ('pub_date','headline')
@@ -30,5 +31,10 @@ An empty choice field should return None for the display name.
 >>> a.save()
 >>> a.get_status_display() is None
 True
+
+Empty strings should be returned as Unicode
+>>> a2 = Article.objects.get(pk=a.id)
+>>> a2.misc_data
+u''
 """
 }