Background and Objective: Among service organizations, health care sector has an important role, because it has the mission of maintaining community well-being. Thus, delivery of high quality health services is essential and should be appropriate with professional standards. Communal understanding of quality concepts helps organization to focus on quality improvement efforts. In addition, understanding of clients’ expectations and perceptions of services quality is one of the first requirements for improving quality of health services. This study was designed to evaluate the quality of health services in Zanjan district health centers based on clients’ expectations and perceptions and to determine the strengths and weaknesses of primary health cares. Materials and Methods: In this cross-sectional study, a self-administered SERVQUAL questionnaire was used for data collection. A total of 300 femaleُs of the health care consumers were selected through random clustering sampling and completed the related questionnaire. The statistical analysis was performed using appropriate software. Results: The results indicated that the health service quality was not concordant with the clients’ expectations and perceptions in all relevant dimensions. Expectations exceeded the perceptions in all dimensions of services quality. Mean score of overall service quality was (-1/22) (p < 0.0001). The reliability dimension (ability to provide the promised service and accurately) was rated as the most important service (-1/13). The lowest mean score (-1/13) belonged to the tangible dimension (p < 0.0001). Conclusion: The results of this study showed that the reliability dimension constitutes the most serious problem facing district health centers. It is recommended that responsible employees and physicians should provide the promised services on time accurately and keep the records of services provided to clients without mistake. It further confirmed that the SERVQUAL elements can help health centers for defining the important areas of services and improving them. Keys word: Services quality, SERVQUAL, Expectations, Perceptions, Zanjan