diff --git a/src/calibre/ebooks/mobi/reader.py b/src/calibre/ebooks/mobi/reader.py
index 0ae3c9ac9d..9576ccb637 100644
--- a/src/calibre/ebooks/mobi/reader.py
+++ b/src/calibre/ebooks/mobi/reader.py
@@ -103,6 +103,8 @@ class EXTHHeader(object):
                 pass
         elif id == 108:
             pass # Producer
+        elif id == 113:
+            pass # ASIN or UUID
         #else:
         #    print 'unhandled metadata record', id, repr(content)
 
diff --git a/src/calibre/ebooks/mobi/writer.py b/src/calibre/ebooks/mobi/writer.py
index 2a71ecd43b..abba173d69 100644
--- a/src/calibre/ebooks/mobi/writer.py
+++ b/src/calibre/ebooks/mobi/writer.py
@@ -1547,6 +1547,31 @@ class MobiWriter(object):
                     rights = 'Unknown'
                 exth.write(pack('>II', EXTH_CODES['rights'], len(rights) + 8))
                 exth.write(rights)
+                nrecs += 1
+
+        # Write UUID as ASIN
+        uuid = None
+        from calibre.ebooks.oeb.base import OPF
+        for x in oeb.metadata['identifier']:
+            if x.get(OPF('scheme'), None).lower() == 'uuid' or unicode(x).startswith('urn:uuid:'):
+                uuid = unicode(x).split(':')[-1]
+                break
+        if uuid is None:
+            from uuid import uuid4
+            uuid = str(uuid4())
+
+        if isinstance(uuid, unicode):
+            uuid = uuid.encode('utf-8')
+        exth.write(pack('>II', 113, len(uuid) + 8))
+        exth.write(uuid)
+        nrecs += 1
+
+        # Write cdetype
+        if not self.opts.mobi_periodical:
+            data = 'EBOK'
+            exth.write(pack('>II', 501, len(data)+8))
+            exth.write(data)
+            nrecs += 1
 
         # Add a publication date entry
         if oeb.metadata['date'] != [] :