Medication nonadherence is a significant clinical problem among individuals taking statins. Poor adherence is often attributable to several reasons, yet most adherence interventions target a single reason. Baseline data were examined from a randomized clinical trial of 236 patients with hyperlipidemia. A latent class analysis was then performed on patients reporting any nonadherence (n = 109). A 4-class solution provided the most optimal fit and differentiation of classes. Class 1 (N = 59, 54%) included patients who reported occasionally forgetting. Class 2 (N = 16, 14%) represented patients who were concerned about side effects. Class 3 (N = 17, 16%) represented patients who reported out-of-routine life events as contributing to nonadherence. Class 4 (N = 17, 16%) represented patients who endorsed a large number reasons indiscriminately. Class membership was almost uniformly unrelated to any patient demographic factors or treatment arm. Each cluster of reasons defining these patients may be best addressed through different intervention strategies.