diff --git a/NEWS b/NEWS
index 74139322..2d78c479 100644
--- a/NEWS
+++ b/NEWS
@@ -28,6 +28,8 @@ What's new in psycopg 2.4
     available.
   - Added missing icon to ZPsycopgDA package, not available in Zope 2.12.9
     (ticket #30). Bug report and patch by Pumukel.
+  - Fixed conversion of negative infinity (ticket #40). Bug report and patch
+    by Marti Raudsepp.
 
 
 What's new in psycopg 2.3.2
diff --git a/tests/types_basic.py b/tests/types_basic.py
index c1392b75..43bae933 100755
--- a/tests/types_basic.py
+++ b/tests/types_basic.py
@@ -113,6 +113,9 @@ class TypesBasicTests(unittest.TestCase):
         self.failUnless(str(s) == "inf", "wrong float quoting: " + str(s))      
         self.failUnless(type(s) == float, "wrong float conversion: " + repr(s))
 
+        s = self.execute("SELECT %s AS foo", (float("-inf"),))
+        self.failUnless(str(s) == "-inf", "wrong float quoting: " + str(s))      
+
     def testBinary(self):
         if sys.version_info[0] < 3:
             s = ''.join([chr(x) for x in range(256)])