This evidence-based report reviews the empiric literature on depression in people with cancer with a focus on three areas: occurrence, assessment, and treatment. More than 350 studies were identified through searches of the English-language literature published between 1966 and September 2001. Reports of occurrence are limited to prevalence studies, and prevalence rates vary widely despite standardized assessments. Rates of major depressive disorder and depressive symptoms comorbid with cancer appear to be 10%-25%. Although multiple instruments are available for assessing depressive symptoms, a clinical interview using Diagnostic and Statistical Manual of Mental Disorders criteria is the standard to which assessments are compared. Some data exist for the efficacy of psychosocial and pharmacologic treatments for depression in this population. No randomized, controlled studies of alternative medicine interventions were identified.