The traditional distinction between active and passive euthanasia requires critical analysis. The conventional doctrine is that there is such an important moral difference between the two that, although the latter is sometimes permissible, the former is always forbidden. This doctrine may be challenged for several reasons. First of all, active euthanasia is in many cases more humane than passive euthanasia. Secondly, the conventional doctrine leads to decisions concerning life and death on irrelevant grounds. Thirdly, the doctrine rests on a distinction between killing and letting die that itself has no moral importance. Fourthly, the most common arguments in favor of the doctrine are invalid. I therefore suggest that the American Medical Association policy statement that endorses this doctrine is unsound. (N Engl J Med 292:78–80, 1975)