diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index ee8afe427e76d296955905b16070ea427d8b729a..cc0bdf658629ef8e27b1b9ce0c386640a89890d3 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Fixed Time#last_year to go back in time, not forward #1278 [fabien@odilat.com]
+
 * Fixed the pluralization of analysis to analyses #1295 [seattle@rootimage.msu.edu]
 
 * Fixed that Time.local(2005,12).months_since(1) would raise "ArgumentError: argument out of range" #1311 [jhahn@niveon.com]
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index f238ca168a831f32aae45420625cc8849a9bea4e..1c9a3523a97c07492a4851fa53d856791680ccb1 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -64,12 +64,12 @@ def years_since(years)
           change(:year => self.year + years)
         end
 
-        # Short-hand for months_ago(1)
+        # Short-hand for years_ago(1)
         def last_year
-          years_since(1)
+          years_ago(1)
         end
         
-        # Short-hand for months_since(1)
+        # Short-hand for years_since(1)
         def next_year
           years_since(1)
         end
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index 6bad622386265a19c8ba07b23675284c203a2249..18ae3219bc397f223686bcc2ddd71372543c3cf8 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -56,6 +56,10 @@ def test_years_since
     # Failure because of size limitations of numeric?
     # assert_equal Time.local(2182,6,5,10),  Time.local(2005,6,5,10,0,0).years_since(177) 
   end
+
+  def test_last_year
+    assert_equal Time.local(2004,6,5,10),  Time.local(2005,6,5,10,0,0).last_year
+  end
   
 
   def test_ago