Between 1951 and 1967, Dr. C. Walton Lillehei trained 134 cardiothoracic surgeons at the University of Minnesota Hospital. Between 1967 and 1979, he trained another 20 surgeons at the New York Hospital-Cornell Medical Center. Twenty-three of these 154 Lillehei trainees became program directors of cardiothoracic programs and in turn trained 477 additional surgeons. Twenty-one of these second-generation trainees became program directors and trained 164 surgeons. Two of these third-generation trainees have become directors and have in turn trained 25 additional trainees. A total of at least 820 cardiothoracic surgeons, currently residing in 36 countries, can trace their preceptor lineage back to Dr. Lillehei. A number of significant clinical and research contributions have been forthcoming from these Lillehei trainees during the past 35 years.