The present study was designed to assess the frequency of different barriers to adherence among persons with insulin-dependent diabetes mellitus (IDDM) and to determine the relationship between such barriers and adherence to insulin injection, glucose testing, and dietary and exercise components of the regimen. The behavior analytic model was used to develop a Barriers to Adherence Scale for adults and adolescents with IDDM. Sixty-five outpatient subjects were then interviewed in their home and reassessed 6 months later. Subjects reported the greatest number of barriers to dietary and exercise adherence and the fewest barriers to insulin injections. Females reported more barriers than males, but age was not associated with barriers scores. Self-report measures of adherence revealed consistent relationships between barriers and all areas of regimen adherence assessed. Adherence indices based on self-monitoring and dietary recall data correlated less consistently with barriers scores. We conclude that the behavior analytic model has great potential for use in the development of psychosocial assessment procedures for diabetes.