Three Hippocratic physicians played critical roles in the prosecution of 23 Nazi doctors charged with murder and torture for conducting lethal medical experiments on concentration camp prisoners. Two of the physicians, Leopold Alexander and Andrew C. Ivy, were Americans, and the other, Werner Leibbrandt, was German. At the 70th anniversary of the Doctors' Trial it is fitting to recall the three's influences and contributions to the formulation of strict research ethics rules, known as the Nuremberg Code. Their contributions help us better understand why they insisted on strict research rules and yet ultimately were unable to apply these rules to their own research. Exploring their contributions at Nuremberg may help us appreciate the continuing difficulty physician-researchers have with accepting public regulation of research.