Understanding the factors that influence differing types of health care utilization within vulnerable groups can serve as a basis for projecting future health care needs, forecasting future health care expenditures, and influencing social policy. In this article the Behavioral Model for Vulnerable Populations is used to evaluate discretionary (physician visits) and non-discretionary (emergency room visits, and hospitalizations) health utilization patterns of a sample of 1466 respondents with one or more vulnerable health classification. Reported vulnerabilities include: (1) persons with substance disorders; (2) homeless persons; (3) persons with mental health problems; (4) victims of violent crime; (5) persons diagnosed with HIV/AIDS; (6) and persons in receipt of public benefits. Hierarchical logistic regression is used on three nested models to model factors that influence physician visits, emergency room visits, and hospitalizations. Additionally, bivariate logistic regression analyses are completed using a vulnerability index to evaluate the impact of increased numbers of vulnerability on all three forms of health care utilization. Findings from this study suggest the Behavioral Model of Vulnerable Populations be employed in future research regarding health care utilization patterns among vulnerable populations. This article encourages further research investigating the cumulative effect of health vulnerabilities on the use of non-discretionary services so that this behavior could be better understood and appropriate social policies and behavioral interventions implemented.