Meta-analyses on psychological treatment for depression in individuals with a somatic disease are limited to specific underlying somatic diseases, thereby neglecting the generalisability of the interventions. To examine the effectiveness of cognitive-behavioural therapy (CBT) for depression in people with a diversity of somatic diseases. Meta-analysis of randomised controlled trials evaluating CBT for depression in people with a somatic disease. Severity of depressive symptoms was pooled using the standardised mean difference (SMD). Twenty-nine papers met inclusion criteria. Cognitive-behavioural therapy was superior to control conditions with larger effects in studies restricted to participants with depressive disorder (SMD = -0.83, 95% CI -1.36 to -0.31, P<0.001) than in studies of participants with depressive symptoms (SMD = -0.16, 95% CI -0.27 to -0.06, P = 0.001). Subgroup analyses showed that CBT was not superior to other psychotherapies. Cognitive-behavioural therapy significantly reduces depressive symptoms in people with a somatic disease, especially in those who meet the criteria for a depressive disorder.