The incident was reported by students in the girls hostel at about 0250 hours and the AIIMS security and staff immediately informed the police.
The body was taken to the emergency wing of AIIMS where doctors pronounced her dead, the police said.
The police have seized the mobile phone of the student Khushboo Chaudhary, 19, for clues. However, no suicide note has been found in the room of the deceased. Khushboo was a resident of Bikaner in Rajasthan and had joined AIIMS on July 10 as a first-year MBBS student.
"According to her friends, she was a cheerful girl and had spent last evening with her friends shopping and going out. According to one of her friends, she had been normally interacting with her friends till a few minutes before the incident was reported," said AIIMS spokesperson Amit Gupta.
A preliminary enquiry by AIIMS has ruled out ragging or any adjustment difficulties as she had been a student at the institute only for six weeks as the possible cause of alleged suicide, he said.
Gupta said that the AIIMS authorities have ordered an internal inquiry into the incident and will be interacting with the police to find out the cause of the alleged suicide. Meanwhile, the parents of Khusboo have been informed by the AIIMS authorities.