Background. This study clarifies the confusion about what factors are consistent predictors of primary care service use, of which preventive services are a major component. A variety of health risk, predisposing, and enabling characteristics were assessed for their association with the use of primary care. Variable selection was guided by the use of the Andersen–Newman Behavioral Model of health service utilization. Methods. The responses of 1512 residents of Oklahoma to the BRFS survey were used in this study. Both probit and logistic analyses were used to assess the use of nine preventive services and a summary index of service use. Results. The results indicate that those at greater risk of illness and least able to use finance services have the lowest rates of use among the nine preventive services individually and when combined as an index of overall primary care use. Conclusions. Problems persist with the adequate distribution of primary care among the medically vulnerable. Furthermore, recent welfare and health reforms may present added obstacles to their access to quality primary care services. The paper concludes with a discussion of policy options that may improve the effectiveness of primary care and redress inequities in the use of these services.