diff --git a/tests.py b/tests.py
index 0c1a6e6..81d2678 100644
--- a/tests.py
+++ b/tests.py
@@ -284,6 +284,28 @@ def test_periodBehavior(self):
             'TEST:20060216T100000/PT2H,20060516T100000/PT2H'
         )
 
+    def test_rrdate_with_period(self):
+        """
+        Test round-trip parsing and serialization of an RRULE with
+        an RDATE using a PERIOD.
+        """
+
+        raw = "BEGIN:VCALENDAR\r\n" \
+            + "VERSION:2.0\r\n" \
+            + "PRODID:test\r\n" \
+            + "BEGIN:VEVENT\r\n" \
+            + "UID:test\r\n" \
+            + "DTSTART:20000101T000000Z\r\n" \
+            + "DURATION:PT1H\r\n" \
+            + "DTSTAMP:20000101T000000Z\r\n" \
+            + "RDATE;VALUE=PERIOD:20000102T000000Z/PT2H\r\n" \
+            + "RRULE:FREQ=WEEKLY\r\n" \
+            + "END:VEVENT\r\n" \
+            + "END:VCALENDAR\r\n"
+        obj = base.readOne(raw)
+        serialized = obj.serialize()
+        self.assertEqual(raw, serialized)
+
 
 class TestVTodo(unittest.TestCase):
     """
diff --git a/vobject/icalendar.py b/vobject/icalendar.py
index 52ff94b..ef9b430 100644
--- a/vobject/icalendar.py
+++ b/vobject/icalendar.py
@@ -876,14 +876,20 @@ def transformFromNative(obj):
             obj.value_param = 'DATE'
             obj.value = ','.join([dateToString(val) for val in obj.value])
             return obj
-        # Fixme: handle PERIOD case
         else:
             if obj.isNative:
                 obj.isNative = False
                 transformed = []
                 tzid = None
                 for val in obj.value:
-                    if tzid is None and type(val) == datetime.datetime:
+                    if obj.value_param == "PERIOD":
+                        if type(val[0]) is datetime.datetime and type(val[1]) is datetime.timedelta:
+                            transformed.append(periodToString(val))
+                            continue
+                        if type(val[0]) is datetime.datetime and type(val[1]) is datetime.datetime:
+                            transformed.append(dateTimeToString(val[0]) + '/' + dateTimeToString(val[1]))
+                            continue
+                    if tzid is None and type(val) is datetime.datetime:
                         tzid = TimezoneComponent.registerTzinfo(val.tzinfo)
                         if tzid is not None:
                             obj.tzid_param = tzid