Background: Although most depressive disorders are treated in primary care and several studies have examined the effects of psychological treatment in primary care, hardly any meta-analytic research has been conducted in which the results of these studies are integrated. Aim: To integrate the results of randomised controlled trials of psychological treatment of depression in adults in primary care, and to compare these results to psychological treatments in other settings. Design of study: A meta-analysis of studies examining the effects of psychological treatments of adult depression in primary care. Setting: Primary care. Method: An existing database of studies on psychological treatments of adult depression that was built on systematic searches in PubMed, PsychINFO, EMBASE, and Dissertation Abstracts International was used. Randomised trials were included in which the effects of psychological treatments on adult primary care patients with depression were compared to a control condition. Results: In the 15 included studies, the standardised mean effect size of psychological treatment versus control groups was 0.31 (95% CI = 0.17 to 0.45), which corresponds with a numbers-needed-to-treat (NNT) of 5.75. Studies in which patients were referred by their GP for treatment had significantly higher effect sizes (d = 0.43; NNT = 4.20) than studies in which patients were recruited through systematic screening (d = 0.13, not significantly different from zero; NNT = 13.51). Conclusions: Although the number of studies was relatively low and the quality varied, psychological treatment of depression was found to be effective in primary care, especially when GPs refer patients with depression for treatment. © British Journal of General Practice.