For Physics - M.Sc. in Physics, or an M.Sc., M.E., or M.Tech. in related disciplines. Candidates with M.Sc. in Mathematics will also be considered at Indian Institute of Astrophysics (IIA) . At  Institute for Plasma Research (IPR) , a Masters degree in Physics, Engineering Physics, Applied Physics, etc., is necessary. Graduates with B.E. or B.Tech. will also be considered at Indian Institute of Astrophysics(IIA), Inter-University Centre for Astronomy and Astrophysics(IUCAA), National Centre for Radio Astrophysics(NCRA),Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR),Raman Research Institute(RRI) and The Institute of Mathematical Sciences(IMSc).

For Mathematics -M.Sc. in Mathematics, or an M.Sc., M.E. or M.Tech. in related disciplines.
For Theoretical Computer Science-  M.Sc., M.E., M.Tech., in Computer Science or related disciplines, and should be interested in the mathematical aspects of computer science. 
At Harish-Chandra Research Institute (HRI) candidates with a Bachelor's degree will also be considered for the integrated M. Sc,Ph. D. programme in Mathematics/Physics.
At The Institute of Mathematical Sciences (IMSc)- Graduates with a B.Sc., B.E., or B.Tech. degree will also be considered for admission to the M.Sc. (by Research) programmes in Mathematics, Theoretical Computer Science, and Physics, as part of an integrated Ph.D. programme in these disciplines. 
At S.N. Bose National Centre for Basic Sciences (SNBNCBS) Talented graduates with B.Sc.Physics, B. E., B. Tech. degrees will be considered for the Integrated Ph.D. programme