Severe psoriasis is associated with excess mortality and increased risk of cardiovascular death. Population-based data evaluating cause-specific mortality in patients with psoriasis are limited. To describe cause-specific mortality in patients with severe psoriasis. We performed a cohort study from 1987 to 2002 of patients ≥18 years using the General Practice Research Database. We compared patients with a psoriasis code and a history of systemic therapy consistent with severe psoriasis (n=3603) with patients with no history of psoriasis (n=14,330). Age- and sex-adjusted Cox models were created for each of the leading causes of death defined by the Centers for Disease Control. Patients with severe psoriasis were at increased risk of death from cardiovascular disease [hazard ratio (HR) 1·57, 95% confidence interval (CI) 1·26-1·96], malignancies (HR 1·41, 95% CI 1·07-1·86), chronic lower respiratory disease (HR 2·08, 95% CI 1·24-3·48), diabetes (HR 2·86, 95% CI 1·08-7·59), dementia (HR 3·64, 95% CI 1·36-9·72), infection (HR 1·65, 95% CI 1·26-2·18), kidney disease (HR 4·37, 95% CI 2·24-8·53) and unknown/missing causes (HR 1·43, 95% CI 1·09-1·89). The absolute and excess risk of death was highest for cardiovascular disease (61·9 and 3·5 deaths per 1000 patient-years, respectively). Severe psoriasis is associated with an increased risk of death from a variety of causes, with cardiovascular death being the most common aetiology. These patients were also at increased risk of death from causes not previously reported, such as infection, kidney disease and dementia. Additional studies are necessary to determine the degree to which excess causes of death are due to psoriasis, its treatments, associated behaviours, or other factors. © The Authors. BJD © 2010 British Journal of Dermatology.