Depression is commonly encountered in primary care settings yet is often missed or suboptimally managed. A number of organizational and educational strategies to improve management of depression have been proposed. The clinical effectiveness and cost-effectiveness of these strategies have not yet been subjected to systematic review. To systematically evaluate the effectiveness of organizational and educational interventions to improve the management of depression in primary care settings. We searched electronic medical and psychological databases from inception to March 2003 (MEDLINE, PsycLIT, EMBASE, CINAHL, Cochrane Controlled Trials Register, United Kingdom National Health Service Economic Evaluations Database, Cochrane Depression Anxiety and Neurosis Group register, and Cochrane Effective Professional and Organisational Change Group specialist register); conducted correspondence with authors; and used reference lists. Search terms were related to depression, primary care, and all guidelines and organizational and educational interventions. We selected 36 studies, including 29 randomized controlled trials and nonrandomized controlled clinical trials, 5 controlled before-and-after studies, and 2 interrupted time-series studies. Outcomes relating to management and outcome of depression were sought. Methodological details and outcomes were extracted and checked by 2 reviewers. Summary relative risks were, where possible, calculated from original data and attempts were made to correct for unit of analysis error. A narrative synthesis was conducted. Twenty-one studies with positive results were found. Strategies effective in improving patient outcome generally were those with complex interventions that incorporated clinician education, an enhanced role of the nurse (nurse case management), and a greater degree of integration between primary and secondary care (consultation-liaison). Telephone medication counseling delivered by practice nurses or trained counselors was also effective. Simple guideline implementation and educational strategies were generally ineffective. There is substantial potential to improve the management of depression in primary care. Commonly used guidelines and educational strategies are likely to be ineffective. The implementation of the findings from this research will require substantial investment in primary care services and a major shift in the organization and provision of care.