Stroke is amenable to the entire spectrum of health services, ranging from prevention of its risk factors, to the treatment of acute stroke and rehabilitation and palliation of stroke. The aim of this study was to determine the number of persons with the capacity to benefit from evidence-based effective stroke services. Population-based survey and registry data along with published, evidence-based recommendations for services were used to determine the number of persons in Eastern Ontario with stroke (including risk factors, acute stroke and chronic stroke) and their related need for services (including prevention programs, diagnostic services, treatment of acute stroke and rehabilitation). These estimates were then compared to the actual provision of these services. Estimates of the need for effective services exceeded the provision of all services with the exception of pharmacologic treatment for diabetes mellitus and carotid endarterectomy for acute stroke. The approach was able to identify both the under-provision and over-provision of evidence-based effective services for stroke. This study has shown that an epidemiologically-based needs assessment could be a useful basis for the planning of health services.