To understand why blacks are under-represented in medical schools and how this situation might be changed, we analyzed statistics on medical-school applicants, medical-school students and college undergraduates. The pool of qualified black applicants to medical schools has not been large enough to achieve appropriate black representation. If black under-representation is to be corrected, the pool of qualified black applicants must be increased. Affirmative-action programs for blacks who are already in college are unlikely to be sufficient by themselves to increase the pool of black applicants substantially. Such programs should therefore be developed for high-school students.