Background: Previous studies have shown increased prevalence of metabolic syndrome in patients with psoriasis. Objectives: To characterize the anthropometric and metabolic profile of Spanish patients with moderate to severe psoriasis compared with controls without psoriasis matched for gender, age and body mass index (BMI), and to evaluate the impact of narrowband ultraviolet B (NB-UVB) therapy on patient profiles. Methods Baseline waist circumference, body fat composition, lipid, carbohydrate and calcium metabolism profile, inflammation markers, homocysteine, vitamins D, B 6 and B 12 and folic acid of 50 patients with psoriasis and 50 matched controls were recorded then evaluated after NB-UVB in patients with psoriasis and correlated with clinical outcome. Results: Despite very similar BMIs, 54% of patients met International Diabetes Foundation criteria for metabolic syndrome compared with 42% of controls (P = 0·01); body fat was 29·9% in patients and 28·0% in controls (P = 0·037), correlating with waist circumference; while patient atherogenic profiles were less favourable, with higher apolipoprotein B and low density lipoprotein cholesterol than controls, and both patients and controls showed insufficient vitamin D serum levels (< 20 ng mL -1). Mean improvement of Psoriasis Area and Severity Index (PASI) after NB-UVB was 78·2%. Ferritin, B 12 and C-reactive protein decreased significantly after NB-UVB therapy. Vitamin D levels reached adequate levels after phototherapy; however, no relationship with PASI improvement was observed. Conclusions: We characterized inflammatory and atherogenic profiles of Spanish patients with psoriasis compared with matched controls. After NB-UVB therapy we demonstrated improvement in psoriasis and some systemic inflammation markers, which were not mediated by enhancement of vitamin D synthesis. © 2012 British Association of Dermatologists.