Noncompliance with therapy is one possible explanation for the observation that long-term graft survival is not sufficiently improved by the development in immunosuppression. The aim of the study was to explore the prevalence, characteristics and risk factors of noncompliance with immunosuppression. A total of 161 adult kidney transplant recipients were inter-viewed about their self-rated health, social support, education, stress from adverse effects and compliance with the immunosuppression. The prevalence of subclinical noncompliance was 54%. Noncompliant patients declared significantly worse self-rated health, less satisfaction with social support and higher stress from adverse effects. Male gender (OR 7.5, CI 2.4-23.39), high stress from adverse effects (OR 12.27, CI 2.44-61.88), fair self-rated health (OR 4.45, CI 1.04-19.55) and fair satisfaction with social support (OR 4.55, CI 1.08-19.24) were predictors of noncompliance. Standardized detection methods should be developed with the aim of identifying patients who are at risk of noncompliance in order to prevent graft loss.