Planned changes to the MCAT exam and the premedical course requirements are intended to enable the assessment of humanistic characteristics and, thus, to select students who are more likely to become physicians who can communicate and relate with patients and engage in ethical decision making. Identifying students who possess humanistic and communication skills is an important goal, but the changes being implemented may not be sufficient to evaluate key personality traits that characterize well-rounded, thoughtful, empathic, and respectful physicians. The author argues that consideration should be given to assessing prospective students' tolerance for ambiguity as part of the admission process. Several strategies are proposed for implementing and evaluating such an assessment. Also included in this paper is an overview of the conceptual and empirical literature on tolerance for ambiguity among physicians and medical students, its impact on patient care, and the attention it is given in medical education. This evidence suggests that if medical schools admitted students who possess a high tolerance for ambiguity, quality of care in ambiguous conditions might improve, imbalances in physician supply and practice patterns might be reduced, the humility necessary for moral character formation might be enhanced, and the increasing ambiguity in medical practice might be better acknowledged and accepted.