The German health care policy debate is affected by proposals demanding the introduction of competitive elements. Analysis of the effects of regulated competition in the Netherlands health care system shows that actual behavioural changes of the key actors of the system differ considerably from expected changes, although incentives within the system have been substantially changed. Sickness funds are not selectively linked with providers and insured patients do not change their insurance company very often. From the point of view of the original reform targets, this preliminary result is quite disappointing. It can be explained by the fact that the relations between sickness funds, general practitioners and insured persons or patients are within a broader framework of health care. Thus, competition does not seem attractive to either of them. If regulated competition became more dominant, several undesirable effects on the so far well-appreciated primary care may be expected.