This study was designed to determine the extent to which differences in criteria for dialysis patient selection and availability of financial resources cause the wide variation in acceptance rates for dialysis in Canada, the United Kingdom, and the United States. We also sought to determine whether there is agreement among nephrologists in the three countries on which patients should not be offered dialysis. We used a cross-sectional survey of all members of the Canadian Society of Nephrology and the Renal Association of Great Britain, and a randomized sample of 800 members of the American Society of Nephrology. Five case vignettes were presented asking for yes/no decisions on offering or not offering dialysis, together with ranking of factors considered important. We also inquired about dialysis resources and physician demographics. We compared responses by country. More nephrologists from the United Kingdom returned responses (83%) than Canadian (53%) or American (36%) nephrologists. American nephrologists offered dialysis more than Canadian or British nephrologists (three of five cases; P < 0.04 to P < 0.001) and ranked patient/family wishes (three of five cases; P < 0.057 to P < 0.0001) and fear of lawsuit (P < 0.04 to P = 0.0012) higher than British or Canadian nephrologists. Canadian and British nephrologists reported their perception of patients' quality of life as a reason to provide (P = 0.0019) or not provide (P = 0.068 to P = 0.0026) dialysis more often than their American counterparts. Despite these differences, nephrologists from each country did not differ by more than 30% on any decision and ranked factors almost identically. Ten percent and 12% of Canadian and British nephrologists, respectively, but only 2% of American nephrologists, reported refusing dialysis due to lack of resources (P < 0.0001). We conclude that the wide variation in dialysis acceptance rates in the three countries is somewhat influenced by differences in patient selection criteria and withholding of dialysis by nephrologists based on financial constraints, but that other factors, such as differences in rates of patient nonreferral for dialysis, contribute more significantly to the variation. Generally agreed on practice guidelines for dialysis patient selection appear possible.