diff --git a/app/helpers/issues_helper.rb b/app/helpers/issues_helper.rb
index afc8b855..b9e11c9f 100644
--- a/app/helpers/issues_helper.rb
+++ b/app/helpers/issues_helper.rb
@@ -36,6 +36,7 @@ module IssuesHelper
   # Returns a string of css classes that apply to the given issue
   def css_issue_classes(issue)
     s = "issue status-#{issue.status.position} priority-#{issue.priority.position}"
+    s << ' overdue' if issue.overdue?
     s
   end
   
diff --git a/app/models/issue.rb b/app/models/issue.rb
index c8befa72..fcac38bd 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -195,6 +195,11 @@ class Issue < ActiveRecord::Base
     self.status.is_closed?
   end
   
+  # Returns true if the issue is overdue
+  def overdue?
+    !due_date.nil? && (due_date < Date.today)
+  end
+  
   # Users the issue can be assigned to
   def assignable_users
     project.assignable_users
diff --git a/test/unit/issue_test.rb b/test/unit/issue_test.rb
index 12b4da33..fee6f78c 100644
--- a/test/unit/issue_test.rb
+++ b/test/unit/issue_test.rb
@@ -190,4 +190,11 @@ class IssueTest < Test::Unit::TestCase
     assert_nil Issue.find_by_id(1)
     assert_nil TimeEntry.find_by_issue_id(1)
   end
+  
+  def test_overdue
+    assert Issue.new(:due_date => 1.day.ago).overdue?
+    assert !Issue.new(:due_date => Date.today).overdue?
+    assert !Issue.new(:due_date => 1.day.from_now).overdue?
+    assert !Issue.new(:due_date => nil).overdue?
+  end
 end