The Kingdom of Saudi Arabia (KSA) recently launched a reform plan for its health care system in 2021 driven by its Vision 2030 initiative. This vision aims to reduce dependence on government resources by transitioning to the national health insurance model and the Cooperative Health Insurance program, especially for the immigrant population. This reform may impact the utilization of health services by citizenship and insurance status. The current study aims to identify factors influencing health insurance enrollment and its impact on outpatient service utilization in the Kingdom of Saudi Arabia. This study used data from the 2018 Saudi Family Health Survey (FHS) as a valuable pre-reform baseline for understanding health insurance enrollment and outpatient service utilization in Saudi Arabia before the 2021 reforms. The survey covers a nationally representative sample from KSA (n=8,274) which contains questions that obtain information about the health insurance enrollment, health care utilization, chronic disease condition and health status of the respondents. We conducted a bivariate analysis using a chi-square test and an independent sample t-test to examine the significance of differences between groups (by nationality and insurance status). We employed multiple binary logistic regression models to measure the association between health insurance enrollment and the demographic and socioeconomic characteristics of the respondents. Further, the multiple Poisson regression model was used to estimate the effect of health insurance status on the utilization of outpatient care. Most of the respondents were Saudis (76.8%) and the number of males (54.9%) respondents were higher than the females. Around 26.2% of the total respondents were insured and the proportion of insured was significantly higher among non-Saudis (72.8%) compared to Saudis (12.1%). The logistic regression showed that individuals with a high monthly income, non-Saudi, males, being married, high level of education and perceived good health were associated with health insurance enrollment. We found health insurance enrollment was associated with lower utilization of outpatient services (co-efficient -0.107; P<0.001). Other factors increasing utilization of outpatient services were being female, having a high monthly income, being never married, having chronic diseases and the perception of bad health. Significant determinants of health insurance enrollment were being non-Saudi, males, having a high income, higher education level and perceived good health status. However, health insurance was associated with lower utilization of outpatient services. The results of the current study should be taken into consideration when planning for the implementation and monitoring reform of the health system in Saudi Arabia.