Background: The paper deals with the issue whether and how far the age of the patient plays a role in treatment decisions. Materials and methods: Recent data from two interview studies on ethical questions in emergency, intensive and geriatric care as well as a survey with general practitioners and internists (both in- and outpatient care) in four European countries are presented. Results: According to this empirical basis there is evidence that the age of the patient does in fact influence treatment decisions, even regarding the withholding of adequate measures. It has to be distinguished between age as an influential factor and the legitimating to allocate or withhold health resources according to the patient’s age. Whether or not such a distinction by age is ethically acceptable, is a matter of debate internationally. Conclusions: The paper gives an overview about the pros and cons of rationing by age and provides a conclusion that the arguments against are prevailing. It closes with (ethical) recommendations for practice.