To examine the relationship of a population's socioeconomic characteristics to its health status and use of health care services, a composite socioeconomic risk index was developed for the Population Health Information System. From a set of 23 socioeconomic indicators derived from public use census data, a summary index was formed from six indicators to generate profiles for the eight health regions of the province. Regional scores were plotted against an index of health status measures and against measures of health care utilization. Strong regional variations were found in all of these measures, and the socioeconomic risk index explained 87% to 92% of the differences in health status and acute hospitalizations. Moreover, regions with the worst health status on our indicators were found to be among the highest consumers of health services. The socioeconomic risk index appears to be a powerful tool in clarifying which benefits in improved health status might accrue from changing the underlying inequities in amenable socioeconomic risk factors, rather than simply increasing services to regions of low health status.