After having his postdoctoral research and short stint of assistant professorship at Baylor College of Medicine, US, he returned to India in 1978 and joined the Department of Biochemistry, IISc as Assistant Professor.
He was promoted to Associate Professor in 1987 and Professor in 1991.
He was the Chairman of Centre for Genetic Engineering, IISc between 1990–93.
For several occasions, he served as visiting professor to Baylor College of Medicine, Harvard Medical School, Ludwig Institute for Cancer Research and University of California at San Diego, US.

In 2003, he accepted the chair of President of Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore.
He was the Chairperson of Department of Biochemistry, IISc (1998–2003) and Molecular Biology and Genetics Unit (MBGU, JNCASR) between 2005–09.
He has served as President of Society of Biological Chemists (India) for two terms between 2000–04.
M.R.S. Rao has been associated as a governing body member or as a scientific advisor to several research institutes in India.
He is the Ex-Chairman of Board of Governors of Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala.

He has served as chairperson or expert member of several scientific councils such as Department of Science and Technology, Department of Biotechnology (DBT), Council of Scientific and Industrial Research (CSIR), Indian Council of Medical Research (ICMR); Science academies such as Indian Academy of Sciences (IAS), National Academy of Sciences, India (NASI), Indian National Science Academy (INSA), Third World Academy of Sciences (TWAS) and science policy making committees in Government of India organisations, Institutions and Universities in India.
He is also active member of Third World Academy of Sciences (TWAS) activities.
He is the chairperson of Task Force on Human Genetics & Genome Analysis of Department of Biotechnology, (DBT) India.
He is member of Governing body of Institute of Bioinformatics and Applied Biotechnology (IBAB), Bangalore.
He is also serving as member of academic council of Poornaprajna Institute of Scientific Research, Bangalore.

Rao has been appointed as a member in the newly constituted National Science and Engineering Research Board (SERB) which will support innovation, research and development in various sciences in India.

He is on the editorial board of several high repute peer reviewed journals and recently has joined as senior member on the editorial board of American Journal of Cancer Research (AJCR).
After having his postdoctoral research and short stint of assistant professorship at Baylor College of Medicine, US, he returned to India in 1978 and joined the Department of Biochemistry, IISc as Assistant Professor. He was promoted to Associate Professor in 1987 and Professor in 1991. He was the Chairman of Centre for Genetic Engineering, IISc between 1990–93. For several occasions, he served as visiting professor to Baylor College of Medicine, Harvard Medical School, Ludwig Institute for Cancer Research and University of California at San Diego, US.
In 2003, he accepted the chair of President of Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore. He was the Chairperson of Department of Biochemistry, IISc (1998–2003) and Molecular Biology and Genetics Unit (MBGU, JNCASR) between 2005–09. He has served as President of Society of Biological Chemists (India) for two terms between 2000–04. M.R.S. Rao has been associated as a governing body member or as a scientific advisor to several research institutes in India. He is the Ex-Chairman of Board of Governors of Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala.
He has served as chairperson or expert member of several scientific councils such as Department of Science and Technology, Department of Biotechnology (DBT), Council of Scientific and Industrial Research (CSIR), Indian Council of Medical Research (ICMR); Science academies such as Indian Academy of Sciences (IAS), National Academy of Sciences, India (NASI), Indian National Science Academy (INSA), Third World Academy of Sciences (TWAS) and science policy making committees in Government of India organisations, Institutions and Universities in India. He is also active member of Third World Academy of Sciences (TWAS) activities. He is the chairperson of Task Force on Human Genetics & Genome Analysis of Department of Biotechnology, (DBT) India. He is member of Governing body of Institute of Bioinformatics and Applied Biotechnology (IBAB), Bangalore. He is also serving as member of academic council of Poornaprajna Institute of Scientific Research, Bangalore.
Rao has been appointed as a member in the newly constituted National Science and Engineering Research Board (SERB) which will support innovation, research and development in various sciences in India.
He is on the editorial board of several high repute peer reviewed journals and recently has joined as senior member on the editorial board of American Journal of Cancer Research (AJCR).
M. R. S. Rao