Introduction: Accessibility is a complex concept and has various dimensions, based on the phenomenon being modeled. Quantification of this concept with the proper dimensions in mind, calls for mathematical indices and models. Spatial accessibility is one of the principal concepts of geography and transportation planning, especially in the social aspects, like justice. Since health is of major concern, universally, including also the developing countries, its inappropriate distribution can lead to unjust supply of its services, and unequal opportunities in accessing them. Spatial accessibility can generally be measured using the two criteria of regional availability and regional accessibility, as was first suggested to be used simultaneously in 1984. Regional Availability, a common index in health care services, measures the number of doctors and other medical experts available per population in need of them. Regional accessibility, on the other hand, characterizes the spatial or geographic distribution of health care services offered to the public in the form of health care centers, presenting the idea of distance from the demand to the supply as an impedance to access them.