The aim of medical school and residency training is to produce well-trained physicians. One problem has been in knowing which applicants to select. Academic criteria have not correlated well with clinical performance. The current study suggests consideration of an important variable that has been found to be associated with exemplary clinical performance. In recent studies a significant relationship between moral reasoning skills and clinical performance has been found for medical students and residents and dental and nursing students. A similar relationship has been found between levels of moral reasoning and malpractice claims among practicing orthopaedic surgeons. Rest has developed the Defining Issues Test, as a paper and pencil, objective test for assessing moral reasoning. With it being deemed appropriate to assess applicants' scientific reasoning, the authors support the development of an assessment of moral reasoning as a selection criterion for medical school and residency training. More research is required. If additional research confirms the relationship of moral reasoning and superior clinical performance, then the results of moral reasoning tests might legitimately be used in the selection process.