Primary care in western Europe is delivered by general practitioners (GPs) but their role within the overall health system is poorly understood. The aim of this article is to present an overview of the characteristics of general practice in the context of health systems and to describe their variability and interrelationships. Data were obtained from two main sources: publications of official organizations and EC research projects. The characteristics of general practice are described and analysed with regard to three features: mode of payment, gatekeeper function and practice organization and workload. Despite their focus on general practice as the cornerstone of the health system, western European countries differ considerably in the major characteristics of primary care. There is variability in the ratio of GPs to population and in the extent to which patients relate to individual physicians. Although all countries have universal health insurance, the mode of payment of GPs differs. In some countries, the gatekeeper function of general practice is more highly developed and the use of specialist services varies accordingly. Practice characteristics such as workload, length of consultation, ordering of tests and reappointments also vary with differences in payment and gatekeeping arrangements. In particular, fee-for-service was associated with weaker physician-patient relationships, reduced attractiveness of general practice, more home visiting and longer consultations. Strong gatekeeping arrangements are not incompatible with high public satisfaction and are associated with lower visit rates. However, strong gatekeeping is not characteristic of fee-for-service arrangements. These findings suggest a need for more concerted research that could inform policy decisions concerning primary care in the USA as well as in Europe.