A hypothetical model was proposed for explaining the relationship between general practitioners' system of payment and the amount of time spent in patient and non-patient work. It was hypothesized that GPs reactions to higher workload vary according to the payment system. In this paper we compare two health care systems which have both mixed systems of payment of GPs. In England and Wales up until April 1990 GPs are partly paid by capitation (approx 45% of their income), partly by allowance (38% of their income) and for a much smaller part fee for service (18% of their income). In the Netherlands GPs are paid by capitation for the publicly insured patients (63% of the average practice list) and fee for service for the privately insured patients. We expect (among other things) a stronger, positive relationship between list size and hours worked in the Netherlands and a comparably strong, negative relationship between list size and booking intervals in the Netherlands and in England and Wales. Drawing on data collected from national surveys of GP workload in the Netherlands and England and Wales these propositions were examined. The results of this comparative analysis showed some support for the propositions in that the relation between list size and number of hours worked in patient related activities is stronger in the Dutch setting than in England and Wales, and about the same strength for the relationship between list size and booking intervals.