Skin irradiation with ultraviolet light B (UV-B) and in particular the emission peak at 311 nm represents an effective therapeutic regimen for psoriasis. Excessive tanning, photoaging, and skin cancerization do occur mainly in subjects with skin phototype I to III. The possibility of developing skin cancer is parallel to the skin surface area under treatment and to the overall irradiation dose. We report here on a new focused phototherapy method releasing UV-B with a peak at 311 nm, which consists in the selective irradiation of single psoriatic patches with a new device equipped with a special optic fiber. The treatment is effective, safe and well tolerated. Psoriasis Area and Severity Index 75 is achieved in 64% of patients after 12 sessions of treatment. The Physician Global Assessment evaluation significantly improves in all treated patients.