Background: Although the Affordable Care Act has been successful in expanding Medicaid to >17 million people, insurance alone may not translate into access to health care. Even among the insured, substantial barriers to accessing services inhibit health care utilization. Objectives: We examined the effect of selected barriers to health care access and the magnitude of those barriers on health care utilization. Research Design: Data come from a 2008 survey of adult enrollees in Minnesota's public health care programs. We used multivariate logistic regression to estimate the effects of perceived patient, provider, and system-level barriers on past year delayed, foregone, and lack of preventive care. Subjects: A total of 2194 adults enrolled in Minnesota Health Care Programs who were mostly female (66%), high school graduates (76%), unemployed (62%), and living in metro areas (67%) were included in the analysis. Results: Reporting problems across all barriers increased the odds of delayed care from 2 times for provider-related barriers (OR=2.0; 95% CI, 1.2-3.3) to >6 times for access barriers (OR=6.2; 95% CI, 3.8-10.2) and foregone care from 2.6 times for family/work barriers (OR=2.6; 95% CI, 1.3-5.1) to >7 times for access barriers (OR=7.1; 95% CI, 3.9-13.1). Perceived discrimination was the only barrier consistently associated with all 3 utilization outcomes. Conclusions: Multiple types of barriers are associated with delayed and foregone care. System-level barriers and discrimination have the greatest effect on health care seeking behavior.