In this descriptive cross-sectional study, we investigated the incidence, determinants, and consequences of subclinical noncompliance with immunosuppressive therapy in 150 adult renal transplant recipients with more than one year posttransplant status. Symptom frequency and symptom distress, and self-care agency were measured by the Transplant Symptom Frequency and Symptom Distress Scale, and the Appraisal for Self-Care Agency Scale, respectively. The Long-Term Medication Behavior Self-Efficacy Scale and a renal transplant knowledge questionnaire were developed as part of this study to measure perceived self-efficacy and knowledge of the therapeutic regimen. Demographic variables were also measured.