Requirements:

Transport of Human Remains

The body of the deceased should be embalmed and placed within a wooden casket, which in turn is to be put in a hermetically sealed outer shipping box. The shipment must be accompanied by:  

1. A death certificate / legalized with Apostille from the Department of state of the state of issuing
2. Certificate of embalming
3. A document certifying that the deceased had not had contagious diseases.

Transport of Cremated Remains

1. A death certificate /legalized with Apostille from the Department of state of the state of issuing
2. A certificate of cremation.

All documents should be legalized with Apostille stamp

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

Embassy: http://www.bulgaria-embassy.org/