Dear Taukeer, there is no specific stream that you should have completed your Graduation in. As long as you have completed your Graduation with a minimum aggregate of 50%, you are eligible for CAT. It is 50% for General Category and 45% for Reserved Categories. But if you are still pursuing your engineering, you should atleast be in the final year to appear for CAT. Then if selected in CAT, you will be given a provisional admission. If you are in 1st,2nd or 3rd year of Engineering, then you are not eligible for CAT.

Yes you can definitely appear for CAT examination after doing BE in mechanical engineering. CAT:- You can enter the world of management through this exam. CAT opens the door to the various IIMs of India. To prepare for it you have to practice maths, aptitude, reasoning and English. Also please read the criteria of individual IIMs before choosing your field, they have a minimum CGPA criteria below which you will not be getting admission.