Requirements:

Transport of Cremated Remains

1. Certified copy of Death certificate
2. Notarized copy of Cremation Certificate
3. Cremains to be placed within an unbreakable urn and wood box
4. Urn to be identified with label stating name if deceased and the date of cremation

Consulates: http://www.state.gov/s/cpr/rls/fco/164194.htm#bhutan

Website: http://www.embassy.org/embassies/bt.html