He received his MD degree from Washington University in St. Louis in 1954 and did a one-year internship at Presbyterian Medical Center with Robert Loeb.

There he split his time between caring for patients receiving experimental cancer chemotherapy and research on recently discovered plasma-cell tumors in mice, similar to human multiple myeloma.

Struck by how little was known about cancer biology, he became interested in protein synthesis in myeloma tumors, and published his first papers on this research.

[2] Nathans returned to Columbia Presbyterian Medical Center for a two-year residency in 1957, again on Robert Loeb's service.

He also became a senior investigator of the Howard Hughes Medical Institute unit at Johns Hopkins School of Medicine in 1982.