Psoriasis is a lifelong, chronic and immune-mediated skin disease affecting approximately 1-3% of the Caucasian population. Pathogenesis of psoriasis is associated with an increased expression of tumor necrosis factor-alpha (TNF-alpha). TNF-alpha is a pro-inflammatory cytokine and important mediator of cachexia. Anti-TNF-alpha therapies are effective in the treatment of psoriasis. The primary end-point was to investigate retrospectively the effect of anti-TNF-therapies on body weight and body mass index (BMI) in patients with psoriasis under treatment with infliximab, etanercept, adalimumab (anti-TNF-alpha group), efalizumab or methotrexate (control group). The patients were treated for 48 weeks. BMI, weight and disease activity were measured at baseline (week 0), weeks 12, 24 and 48. At week 24 a significant increase in body weight and BMI in the anti-TNF-alpha treatment group compared to the control was observed. BMI and body weight did not interfere with the drugs' efficacy. We report a significant weight-gain associated with three different anti-TNF-alpha therapies in a large number of patients affected with psoriasis.