Twenty psychologists were interviewed about an ethical dilemma that they had found to be particularly difficult to resolve. In just under half of the cases the dilemma involved a perceived conflict of ethical principles (e.g., the welfare of the consumer vs. the right to privacy). In the other cases, the psychologists were prevented from following an ethically prescribed course of action by some nonethical consideration such as contractural obligation, legal requirement, or the demands of an employer. We discuss the implications (...) of these two sorts of dilemmas for psychological practice and make some suggestions for proactive approaches to ethical problem solving. (shrink)