Medication noncompliance is a significant problem in medical practice, but many intervention strategies developed for noncompliant patients (such as tangible rewards, contingency contracting) are not practical for the large numbers of patients seen by private practitioners on an ongoing basis. Based upon a review of the literature concerning the key determinants affecting compliance, the authors have developed a practical, rational, and systematic approach to assessing medication compliance that may serve as a guide for psychiatrists in formulating consultation recommendations, in liaison teaching activities, and in clinical psychiatric practice. Special emphasis is placed upon the identification of psychiatric syndromes that may negatively affect compliance. Implications for compliance-related research in consultation-liaison psychiatry are also discussed.