Severo Ochoa de Albornoz (Spanish: [seˈβeɾo oˈtʃoa ðe alβoɾˈnoθ]; 24 September 1905 – 1 November 1993) was a Spanish physician and biochemist, and winner of the 1959 Nobel Prize in Physiology or Medicine together with Arthur Kornberg for their discovery of "the mechanisms in the biological synthesis of deoxyribonucleic acid (DNA)".

His father was Severo Manuel Ochoa (who he was named after), a lawyer and businessman, and his mother was Carmen de Albornoz.

He studied with father Pedro Arrupe, and Juan Negrín was his teacher:[4] Negrin opened wide, fascinating vistas to my imagination, not only through his lectures and laboratory teaching, but through his advice, encouragement, and stimulation to read scientific monographs and textbooks in languages other than Spanish.

Ochoa spent the summer of 1927 at University of Glasgow working with D. Noel Paton on creatine metabolism and improving his English skills.

He also refined the assay procedure further and upon returning to Spain he and Valdecasas submitted a paper describing the work to the Journal of Biological Chemistry, where it was rapidly accepted,[6] marking the beginning of Ochoa's biochemistry career.

His creatine and creatinine work led to an invitation to join Otto Meyerhof's laboratory at the Kaiser Wilhelm Institute for Biology in Berlin-Dahlem in 1929.

At that time the institute was a "hot bed" of the rapidly evolving discipline of biochemistry, and thus Ochoa had the experience of meeting and interacting with scientists such as Otto Heinrich Warburg, Carl Neuberg, Einar Lundsgaard, and Fritz Lipmann in addition to Meyerhof who had received the Nobel Prize in Physiology and Medicine less than a decade earlier.

He then began postdoctoral study at the National Institute for Medical Research in London, where he worked with Henry Hallett Dale.

[11] Ochoa continued research on protein synthesis and replication of RNA viruses until 1985, when he returned to now democratic Spain where he was a science advisor.

[12] A new research center in the Autonomous University of Madrid (UAM), that was planned in the 1970s, was finally open in 1975 (CBM) and named, after his dead, the Centro de Biología Molecular Severo Ochoa.

In June 2011, the United States Postal Service issued a stamp honoring him,[15] as part of the American Scientists collection, along with Melvin Calvin, Asa Gray, and Maria Goeppert-Mayer.