Urticarian vasculitis (UV) is an anatomoclinical disorder characterized by the association of urticarian papules lasting for more than 24 hours with histological cutaneous vasculitis. Several etiologies are associated with the disease. We report the case of a 30-year-old woman with a-two-month history of urticarial purpuric and necrotic cutaneous lesions of the low limbs. These lesions occurred after oral sulfamethoxazole-trimethoprime ingestion, 2 weeks before the skin eruption. Histological examination revealed a leucocytoclasic vasculitis and direct immunofluorescence showed a perivascular IgG and C3 deposits. Immunological, allergological and radiological investigations were normal. The pharmacological enquiry confirmed the imputability of sulfamethoxazole-trimethoprime in the onset of skin eruption. Mild cutaneous improvement was observed after 3 months of treatment with prednisone 0,5 mg/Kg/day. Drug induced urticaria constitutes a rare etiology of UV. Sulfaminthoxazole-trimethoprime imputability has not been reported before among the drug responsible for UV. Management of patients is difficult and improvement usually occurs after several months because of the resistance of the skin lesions.