This study examines the system dimensions of need, barriers to receiving services, and utilization within a single mental health service area. The gap between estimates of service need and service utilization is conceptualized as due to a set of specific barriers covering the access attributes of availability, accessibility, acceptability and affordability. Data from community telephone surveys (N = 2183) of mental health need are analyzed to determine the relationship between the system dimensions of need, barriers and utilization. Respondents were able to distinguish among different types of service barriers. Those in the service gap were potentially more influenced by barriers than the rest of the sample, as were, paradoxically, those who had utilized services within the past year. The implications of these findings for service provision and system design are discussed.