diff --git a/django/template/defaultfilters.py b/django/template/defaultfilters.py
index 71e5bd61ea..9734124c88 100644
--- a/django/template/defaultfilters.py
+++ b/django/template/defaultfilters.py
@@ -1,6 +1,12 @@
 """Default variable filters."""
 
 import re
+
+try:
+    from decimal import Decimal, InvalidOperation, ROUND_HALF_UP
+except ImportError:
+    from django.utils._decimal import Decimal, InvalidOperation, ROUND_HALF_UP
+
 import random as random_module
 try:
     from functools import wraps
@@ -45,7 +51,6 @@ def stringfilter(func):
 # STRINGS         #
 ###################
 
-
 def addslashes(value):
     """
     Adds slashes before quotes. Useful for escaping strings in CSV, for
@@ -92,6 +97,18 @@ def fix_ampersands(value):
 fix_ampersands.is_safe=True
 fix_ampersands = stringfilter(fix_ampersands)
 
+# Values for testing floatformat input against infinity and NaN representations,
+# which differ across platforms and Python versions.  Some (i.e. old Windows
+# ones) are not recognized by Decimal but we want to return them unchanged vs. 
+# returning an empty string as we do for completley invalid input.  Note these
+# need to be built up from values that are not inf/nan, since inf/nan values do 
+# not reload properly from .pyc files on Windows prior to some level of Python 2.5 
+# (see Python Issue757815 and Issue1080440).
+pos_inf = 1e200 * 1e200
+neg_inf = -1e200 * 1e200
+nan = (1e200 * 1e200) / (1e200 * 1e200)
+special_floats = [str(pos_inf), str(neg_inf), str(nan)]
+
 def floatformat(text, arg=-1):
     """
     Displays a float to a specified number of decimal places.
@@ -119,24 +136,42 @@ def floatformat(text, arg=-1):
     * {{ num1|floatformat:"-3" }} displays "34.232"
     * {{ num2|floatformat:"-3" }} displays "34"
     * {{ num3|floatformat:"-3" }} displays "34.260"
+    
+    If the input float is infinity or NaN, the (platform-dependent) string
+    representation of that value will be displayed.
     """
+        
     try:
-        f = float(text)
-    except (ValueError, TypeError):
+        input_val = force_unicode(text)
+        d = Decimal(input_val)
+    except UnicodeEncodeError:
         return u''
+    except InvalidOperation:
+        if input_val in special_floats:
+            return input_val
+        else:
+            return u''
     try:
-        d = int(arg)
+        p = int(arg)
     except ValueError:
-        return force_unicode(f)
+        return input_val
+    
     try:
-        m = f - int(f)
-    except OverflowError:
-        return force_unicode(f)
-    if not m and d < 0:
-        return mark_safe(u'%d' % int(f))
+        m = int(d) - d
+    except (OverflowError, InvalidOperation):
+        return input_val
+    
+    if not m and p < 0:
+        return mark_safe(u'%d' % (int(d)))
+    
+    if p == 0:
+        exp = Decimal(1)
     else:
-        formatstr = u'%%.%df' % abs(d)
-        return mark_safe(formatstr % f)
+        exp = Decimal('1.0') / (Decimal(10) ** abs(p))
+    try:
+        return mark_safe(u'%s' % str(d.quantize(exp, ROUND_HALF_UP)))
+    except InvalidOperation:
+        return input_val
 floatformat.is_safe = True
 
 def iriencode(value):
diff --git a/tests/regressiontests/defaultfilters/tests.py b/tests/regressiontests/defaultfilters/tests.py
index 9e360fc061..a97596f4d7 100644
--- a/tests/regressiontests/defaultfilters/tests.py
+++ b/tests/regressiontests/defaultfilters/tests.py
@@ -13,15 +13,15 @@ u'0.1'
 u'0.0'
 >>> floatformat(0.0)
 u'0'
->>> floatformat(7.7,3)
+>>> floatformat(7.7, 3)
 u'7.700'
->>> floatformat(6.000000,3)
+>>> floatformat(6.000000, 3)
 u'6.000'
 >>> floatformat(6.200000, 3)
 u'6.200'
 >>> floatformat(6.200000, -3)
 u'6.200'
->>> floatformat(13.1031,-3)
+>>> floatformat(13.1031, -3)
 u'13.103'
 >>> floatformat(11.1197, -2)
 u'11.12'
@@ -35,10 +35,23 @@ u'8.280'
 u''
 >>> floatformat(13.1031, u'bar')
 u'13.1031'
+>>> floatformat(18.125, 2) 
+u'18.13' 
 >>> floatformat(u'foo', u'bar')
 u''
+>>> floatformat(u'¿Cómo esta usted?')
+u''
 >>> floatformat(None)
 u''
+>>> pos_inf = float(1e30000)
+>>> floatformat(pos_inf) == unicode(pos_inf)
+True
+>>> neg_inf = float(-1e30000)
+>>> floatformat(neg_inf) == unicode(neg_inf)
+True
+>>> nan = pos_inf / pos_inf
+>>> floatformat(nan) == unicode(nan)
+True
 
 >>> addslashes(u'"double quotes" and \'single quotes\'')
 u'\\"double quotes\\" and \\\'single quotes\\\''