The 39ft x 27ft envelop was made in a period of ten days last month by a group of 24 students belonging to the faculties of Fine Arts, Engineering, Architecture and Law, a varsity official said.
The envelop is addressed to the United Nation Peacekeeping Operation and carries a message for world peace and human brotherhood.
The message on the envelop carries the signature of more than ten thousand youth, the AMU spokesperson said.
A copy of the Guinness certificate was released to reporters by a senior varsity official today.
According to the Guinness Book of World Records, the record for the largest envelop till now was held by a UK-based organisation Stanley Gibbons Co. That envelop, also made by a group of students, was 32ft x 23ft.