diff --git a/src/ISO8601.cpp b/src/ISO8601.cpp
index 0295a96b6..ba2d68d7e 100644
--- a/src/ISO8601.cpp
+++ b/src/ISO8601.cpp
@@ -1215,6 +1215,20 @@ void ISO8601d::operator-- ()
   _date = yesterday._date;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// Postfix decrement by one day.
+void ISO8601d::operator-- (int)
+{
+  ISO8601d yesterday = startOfDay () - 1;
+  yesterday = ISO8601d (yesterday.month (),
+                        yesterday.day (),
+                        yesterday.year (),
+                        hour (),
+                        minute (),
+                        second ());
+  _date = yesterday._date;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 void ISO8601p::clear ()
 {
diff --git a/src/ISO8601.h b/src/ISO8601.h
index 85833640d..c3a24ab61 100644
--- a/src/ISO8601.h
+++ b/src/ISO8601.h
@@ -86,6 +86,7 @@ public:
   ISO8601d& operator-= (const int);
   time_t operator- (const ISO8601d&);
   void operator-- ();    // Prefix
+  void operator-- (int); // Postfix
 
 private:
   void clear ();