The article addresses the issue of rationing health care services, a topic currently being hotly debated in many countries. The author argues that the aspect of causal responsibility ought to play a decisive role in the allocation of limited medical resources. Starting out from Ronald Dworkin's distinction between option luck and brute luck, the appropriate and meaningful uses of the term causal responsibility are clarified first. A discussion of the conditions which might justify giving lower priority to patients whose illnesses (...) are the result of unhealthy behavior, like e.g. alcohol abuse, follows. Causal responsibility is then viewed in the context of private health insurance and the club model of organ donation. It is argued that individuals themselves are basically responsible for their decisions regarding insurance coverage and membership in organ donors' clubs. Causal responsibility is shown to be a more suitable criterion for rationing scarce medical resources than other criteria which might alternatively be considered, such as patients' age. (shrink)