Twenty children age 14 months to 12 years with photoresponsive dermatoses were treated with ultraviolet B (UVB) phototherapy over four years. Ten children had psoriasis, five had pityriasis lichenoids, and five had atopic dermatitis. All received short courses (average 34 treatments) of phototherapy with either no maintenance or short maintenance. Treatment was effective and well tolerated in most patients, and no serious side effects were seen. Patients with psoriasis and pityriasis lichenoides cleared completely. No patient with atopic dermatitis cleared completely, but all were moderately improved, with reduction of the extent of eczema and decreased pruritus. It appears that UVB phototherapy is a valuable and safe therapeutic option for selected children who do not respond to other treatments.