hi,

you have to score minimum of 55% marks / 5.5 in B.E. /B.Tech./M.Sc. in your branch.

then there is an interview and a written test.
Candidates who have graduated from out of iit, have to have a good GATE score.
B.Tech. graduates from the IITs with CGPA/CPI of 8.0 or above would be eligible to admission without having to appear in GATE.
Candidates belonging to SC/ST/PD categories would be eligible for relaxations, as per norms, in the selection criteria.

hope it helped