Health care systems face pressure to increase the quality of health care at the same time with pressure to reduce public spending. The attempt to overcome the gap between needs and opportunities can be resolved through the introduction of public-private partnerships. Goals of this study are to investigate variation of the number, form and efficiency of private providers of general/family medicine services in primary health care and the contribution of socioeconomic and demographic environment on those variations, among counties. Socioeconomic and demographic factors are identified as independent variables that influence the health care need and utilization and consequently the decision of private entities to engage in the provision of health care services. This study extended previous studies because it has introduced socioeconomic and demographic variables. This may shed same new lights on the relationship between private providers of health service and efficiency of providing health service in primary health care. PUBLICATION ABSTRACT