At the time of this interview, Dr. Xavier Pi-Sunyer was a Professor of Medicine at Columbia University and Co-Director of the Nutritional Obesity Research Center. Dr. Pi-Sunyer discusses his formative years in Spain, France, Mexico, and finally the US. He highlights his internship/residency at the former St. Luke’s Hospital; introduction to endocrinology at St. Bartholomew’s Hospital, London, England, continued training in public health at Harvard University and his return to St. Luke’s, via Nigeria and Boston, where he became acquainted with Dr. Theodore Van Itallie. Dr. Van Itallie drew him back to New York to help establish the Endocrine Division and research laboratories for nutrition and metabolic research where the team carried out various grant-funded research projects. The most significant the discovery out of which is the hormone leptin. Dr. Pi-Sunyer also provides information on his own family, hobbies and interests, and comments on the mergers of St. Luke’s with Roosevelt Hospital and later the Continuum Health Partners.