Background: The increase in the older adult population has resulted in a higher demand for outpatient health services and subsequently increased costs paid by older adults. Objectives: This study conducted in Rasht aimed to determine the utilization of outpatient health services among older adults covered by comprehensive health service centers and the factors associated with it. Methods: This cross-sectional analytical study was conducted on 384 older adults aged 60 years and older covered by comprehensive health service centers. The sampling method was stratified random sampling based on consecutive sampling. The information required was collected through a researcher-made two-part questionnaire, including individual-social characteristics and outpatient services, via interviews. Data were analyzed using SPSS version 21 software. The significance level of the tests was considered to be P < 0.05. Results: The results showed that 82.8% of the older adults required outpatient services and 90.9% of them actually received these services. Out of the total, 65.1% went to private sector facilities, 17% to public facilities, and the remaining 18% visited facilities in both sectors. The main reasons for not utilizing outpatient services were the lack of money and the inability to pay. Factors such as place of residence (P = 0.014, OR = 2.417), the presence of chronic disorders (P = 0.047, OR = 1.689), health status (P = 0.012, OR = 0.619), and education level (P = 0.05, OR = 0.763) were found to be associated with the utilization of outpatient services. Conclusions: Two-thirds of the sample had chronic diseases, most of them received outpatient services from the private sector, and about 75% of those who did not receive the service could not afford the costs. Therefore, it is necessary to improve the quality of outpatient services in the public sector and enhance their accessibility. Some individuals were unaware of health screenings for older adults in the comprehensive health services centers, so informing them about these services can be useful in promoting their utilization by older adults and reducing the costs of outpatient services.