Yes, caste certificate is necessary at the time applying for NEET 2018.Before applying for NEET you need to collect following things:Make sure you belong to central govt. accepted reserved caste. Some castes are reserved category in a particular state only.Make sure your name and other details in caste certificate matches 10th and 12th marksheet.In case of any discrepancies you can always ask cbse helpline to suggest you what to do next.