Ochoa was born in Luarca (Asturias), Spain.
His father was Severo Manuel Ochoa, (who he was named after), a lawyer and businessman,and his mother was Carmen de Albornoz.
Ochoa was the nephew of Álvaro de Albornoz (President of the Second Spanish Republic that was exiled, 1947–1951), and a cousin of the poet and critic Aurora de Albornoz.
His father died when Ochoa was seven, and he and his mother moved to Málaga, where he attended elementary school through high school.
 His interest in biology was stimulated by the publications of the Spanish neurologist and Nobel laureate Santiago Ramón y Cajal.
In 1923, he went to the University of Madrid Medical School, where he hoped to work with Cajal, but Cajal retired.
He studied with father Pedro Arrupe, and Juan Negrín was his teacher.

Negrín encouraged Ochoa and another student, José Valdecasas, to isolate creatinine from urine.
The two students succeeded and also developed a method to measure small levels of muscle creatinine.
Ochoa spent the summer of 1927 in Glasgow working with D. Noel Paton on creatine metabolism improving his English skills.
During the summer he 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, marking the beginning of Ochoa's biochemistry career.

Ochoa completed his undergraduate medical degree in the summer of 1929 and developed an interest in going abroad to gain further research experience.
His previous 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 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.

In 1930 Ochoa returned to Madrid to complete research for his MD thesis, which he defended that year.
In 1931, a newly minted MD, he married Carmen García Cobián, he did not have any children.
He then began postdoctoral study at the London National Institute for Medical Research (NIMR), where he worked with Henry Hallett Dale.
His London research involved the enzyme glyoxalase and was an important departure in Ochoa's career in two respects.
First, the work marked the beginning of Ochoa's lifelong interest in enzymes.
Second, the project was at the cutting edge of the rapidly evolving study of intermediary metabolism.
Ochoa was born in Luarca (Asturias), Spain. His father was Severo Manuel Ochoa, (who he was named after), a lawyer and businessman,and his mother was Carmen de Albornoz. Ochoa was the nephew of Álvaro de Albornoz (President of the Second Spanish Republic that was exiled, 1947–1951), and a cousin of the poet and critic Aurora de Albornoz. His father died when Ochoa was seven, and he and his mother moved to Málaga, where he attended elementary school through high school.  His interest in biology was stimulated by the publications of the Spanish neurologist and Nobel laureate Santiago Ramón y Cajal. In 1923, he went to the University of Madrid Medical School, where he hoped to work with Cajal, but Cajal retired. He studied with father Pedro Arrupe, and Juan Negrín was his teacher.
Negrín encouraged Ochoa and another student, José Valdecasas, to isolate creatinine from urine. The two students succeeded and also developed a method to measure small levels of muscle creatinine. Ochoa spent the summer of 1927 in Glasgow working with D. Noel Paton on creatine metabolism improving his English skills. During the summer he 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, marking the beginning of Ochoa's biochemistry career.
Ochoa completed his undergraduate medical degree in the summer of 1929 and developed an interest in going abroad to gain further research experience. His previous 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 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.
In 1930 Ochoa returned to Madrid to complete research for his MD thesis, which he defended that year. In 1931, a newly minted MD, he married Carmen García Cobián, he did not have any children. He then began postdoctoral study at the London National Institute for Medical Research (NIMR), where he worked with Henry Hallett Dale. His London research involved the enzyme glyoxalase and was an important departure in Ochoa's career in two respects. First, the work marked the beginning of Ochoa's lifelong interest in enzymes. Second, the project was at the cutting edge of the rapidly evolving study of intermediary metabolism.
Severo Ochoa