Hi,

For Combined Defence Services Examination, candidates need to just have graduation in any recognized field. So, if you have done your MBBS from a foreign nation and you had nationality of India, you can surely give the CDS examination. As you have completed MBBS, you must have kept Biology at class 12. So, you will be eligible only for IMA and OTA. Air force and Navy needs physics and Mathematics or a graduation in engineering.

Check the following link for detailed information about the examination: https://competition.careers360.com/articles/cds-exam