diff --git a/src/ISO8601.cpp b/src/ISO8601.cpp
index d6d16b203..71671072c 100644
--- a/src/ISO8601.cpp
+++ b/src/ISO8601.cpp
@@ -798,6 +798,14 @@ bool ISO8601p::parse (const std::string& input, std::string::size_type& start)
   return false;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// Static
+bool ISO8601d::leapYear (int year)
+{
+  return ((! (year % 4)) && (year % 100)) ||
+         ! (year % 400);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Static
 int ISO8601d::dayOfWeek (const std::string& input)
@@ -817,6 +825,7 @@ int ISO8601d::dayOfWeek (const std::string& input)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// Static
 int ISO8601d::length (const std::string& format)
 {
   int len = 0;
diff --git a/src/ISO8601.h b/src/ISO8601.h
index 0038b2552..2ee9b0432 100644
--- a/src/ISO8601.h
+++ b/src/ISO8601.h
@@ -44,6 +44,8 @@ public:
   operator time_t () const;
   bool parse (const std::string&, std::string::size_type&, const std::string& format = "");
 
+  static bool leapYear (int);
+
   static int dayOfWeek (const std::string&);
 
   static int length (const std::string&);
diff --git a/test/iso8601d.t.cpp b/test/iso8601d.t.cpp
index dbd1f2712..bdf3682f0 100644
--- a/test/iso8601d.t.cpp
+++ b/test/iso8601d.t.cpp
@@ -71,7 +71,7 @@ void testParse (
 ////////////////////////////////////////////////////////////////////////////////
 int main (int argc, char** argv)
 {
-  UnitTest t (788);
+  UnitTest t (792);
 
   ISO8601d iso;
   std::string::size_type start = 0;
@@ -218,6 +218,12 @@ int main (int argc, char** argv)
 
   try
   {
+    // Leap year.
+    t.ok    (ISO8601d::leapYear (2008), "2008 is a leap year");
+    t.notok (ISO8601d::leapYear (2007), "2007 is not a leap year");
+    t.ok    (ISO8601d::leapYear (2000), "2000 is a leap year");
+    t.notok (ISO8601d::leapYear (1900), "1900 is not a leap year");
+
     t.is (ISO8601d::dayOfWeek ("SUNDAY"),    0, "SUNDAY == 0");
     t.is (ISO8601d::dayOfWeek ("sunday"),    0, "sunday == 0");
     t.is (ISO8601d::dayOfWeek ("Sunday"),    0, "Sunday == 0");