Porter was elected a Fellow of the Royal Society (FRS) in 1964. He won the Gairdner Foundation International Award in 1966. In 1972, Porter shared the Nobel Prize in Physiology or Medicine with Gerald M. Edelman for determining the chemical structure of an antibody. Using the enzyme papain, he broke the blood's immunoglobin into fragments, making them easier to study. He also looked into how the blood's immunoglobins react with cellular surfaces. He subsequently worked with colleagues Kenneth BM Reid, Robert Sim and Duncan Campbell on developing understanding of the Complement Proteins associated with defence against infection.