The goal of this study was to explore patterns and explanations of adherence to antiretroviral therapies from the patient's perspective. It consisted of 78 in-depth interviews with patients attending an HIV clinic in New Orleans, Louisiana, to whom combination therapy had been prescribed. Interviews explored patient's definitions of adherence, beliefs about consequences of nonadherence, reasons for current and past adherence behavior, and contextual issues such as drug and alcohol use and social support. Respondents reported nine distinct patterns of adherence, which they perceived to have different consequences and causes. These patterns hid variations because respondents could have more than one pattern simultaneously and patterns were not stable over time. Although there are gold standards for adherence measurement, such as directly observed therapy, these measurements are most frequently used to classify respondents as adherers or nonadherers based on whether they take a certain percentage of their medication. Such a categorization is simplistic and does not reflect the complexity of adherence patterns.