Chronic ulcerative stomatitis (CUS) has recently been described as a new disease entity characterized by chronic ulceration of oral mucosa which responds to treatment with hydroxychloroquine. It has a particular type of stratified epithelium-specific, antinuclear autoantibody as an immunological marker. Twelve cases have been reported in the literature. We present a 40-year-old woman with an 11-year history of chronic oral ulcerations. Other dermatological diseases, including oral lichen planus, pemphigus vulgaris and cicatricial pemphigoid, as well as bullous lupus erythematosus, were excluded. The clinical diagnosis of CUS was confirmed on the grounds of the immunological and ultrastructural findings. The lesions initially responded to high doses of systemic corticosteroids but relapsed promptly after dose reduction. Dapsone was ineffective. Hydroxychloroquine, given at a dosage of 200-400 mg/day, led to a complete and long-lasting remission.