Dear candidate,No, diploma candidates are not eligible for GATE exam. To be eligible to appear in GATE examination, you must have completed Bachelor's degree in Engineering/Technology or you must be in final year of Graduation course. Since, you have not pursued Graduation course, you are no eligible , so I suggest you to opt for B.E/B.Tech course after completion of your Diploma course, so, that you are eligible to write GATE examination. But after completion of B.Tech/B.E degree, you can apply for GAte exam. Hope the answer is helpful.Good luck!