Hey.

AIIMS PG entrance test is conducted twice in a year. And there is no limit on the total number of attempts in a year or even generally. So you can attempt the AIIMS PG entrance as many times as you like. Make sure that you are eligible though. You must possess an MBBS degree  recognized by Medical Council of India/Dental Council of India. You must have completed the compulsory one-year rotatory internship on the specified date. If you belong to the general/OBC Category, you need to score minimum of 55% aggregate marks in MBBS, while the SC/ST category candidates must secure an aggregate of 50%.

Best of luck