Aim: To detect in patients with psoriasis the adverse effects during TNF-alpha inhibitor therapy. Material and methods: Fifty-seven patients with psoriasis, aged between 12 and 75 years were analyzed. They were treated with different TNF-alpha antagonists, the maximum treatment duration being 59 months. All patients were followed monthly after the initiation of therapy by clinical checkup, then every 3 months during the first 6 months of treatment by laboratory screening, and then every 6 month. Chest x-ray and tuberculin intradermal skin test were performed annually or as needed. All symptoms reported by patients were recorded, the treating doctor deciding the need for additional investigations or specialist consult. Results: Of the total of 57 patients with psoriasis on biological therapy, 9 patients developed diseases requiring temporary or permanent discontinuation of therapy. The recorded adverse reactions were: infectious (pulmonary tuberculosis, pulmonary empyema), oncologic (rectal cancer, renal cancer), dermatologic (vesiculobullous erythema multiforme major, nodular hypodermtis, secondary erythroderma, and hives) disorders. Conclusions: Despite its adverse reactions, biological therapy is safe and is a necessary tool in the treatment of moderate and severe forms of psoriasis unresponsive to other treatments.