Ashtekar's research focuses on classical general relativity and quantum gravity. He has also contributed to quantum field theory, gauge theories and, more generally, to the interface of geometry and physics. He has authored or co-authored over 230 scientific papers and written (co-)edited 7 scientific books. His reformulation of general relativity as a gauge theory has led to loop quantum gravity, an approach to the unification of general relativity and quantum physics that is now being pursued in dozens of research groups world wide. He has continued to play a seminal role in the development of this field as well as its sub-field called loop quantum cosmology. The 25th anniversary of his paper that launched the loop quantum gravity program was celebrated at an international conference in Madrid, Spain in June 2011.

His scientific contributions have been recognized internationally through numerous honors. Early in his career, he received an Alfred P. Sloan Research Fellowship. He has given over 130 invited, plenary talks in various conferences and workshops world-wide, and has served on all Editorial Boards of all the major journals in his field. He is a Fellow the the American Association for Advancement of Science and the American Physical Society. He is one of only 51 Honorary Fellows of the Indian Academy of Sciences drawn from the international community. He won the Senior Forschungspreis of the Alexander von Humboldt Foundation. He has given numerous distinguished lectures in the U.S., Europe, India and Israel. He has held the Krammers Visiting Chair in Theoretical Physics at the University of Utrecht, The Netherlands, a Senior Visiting Fellowship of the British Science and Engineering Research Council and the Sir C. V. Raman Chair of the Indian Academy of Science. He holds a visiting professorship at the Beijing Normal University.

Ashtekar's research has also been widely reported in semi-popular media, sometimes as cover stories. These include Nature, Science, The Economist, US News and World Report, New Scientist, Fox News, MSNBC, Spektrum, Bild der Wissenschaft, Geo, La Recherche, Volksprant as well as Australian, Asian and South American press. The New York Times published a feature article on him and his research. He also featured prominently in the German documentary Kosmos prepared in 2008 for the celebration of Max Planck's 150th birthday.

Ashtekar has had a distinguished service record. In particular he served as a Senior Consultant on Science and Technology for the United Nations Development Office, on policy and oversight committees of the National Science Foundation, Max Planck Society of Germany and Science Research Council of the U.K. and on scientific advisory boards of institutes in Canada, Europe and India.