If you didn't apply for CAT then there are many other MBA Entrance exams like CMAT, MAT, XAT, NMAT etc. for which you can appear if you are aiming top B School for Management programme.

CMAT : CMAT is one of the recently launched MBA programme conducted by AICTE. To apply for this programme you should have minimum 50% in your graduation to apply.

MAT: MAT is conducted four times in a year in the month of February, May, September, December conducted by AIMA. To apply for the exam you should be graduate in any of the decipline from recognised University or final year of Graduation student also can apply.

XAT: XAT is conducted by XLRI Jamshedpur. To apply for the exam you should be graduate in any of the decipline from recognised University or final year of Graduation student also can apply.

NMAT: NMAT is conducted by Narsee Monjee Institute of Management Studies. To apply for the programme you should have minimum 50% in your graduation or final year of Graduation student also can apply.

You can check all about the detail & information for MBA Exams with given below link.

MBA Entrance exams in India

Good Luck!