Sixty-six confirmed cases of Bowen's disease (intraepidermal squamous cell carcinoma) were seen from 1965 through 1976: twenty-four cases were treated surgically-four by excision (two recurrences) and twenty by desiccation and curettage (four recurrences); one was treated with x-ray radiation; and forty-one were treated with topical 5-fluorouracil (5-FU) (three recurrences). Of the six surgical recurrences (25% recurrence), one was retreated by desiccation and curettage and five with 5-FU. Of the three recurrences after 5-FU (8% recurrence), all three were successfully retreated with 5-FU. In view of the generally high recurrence rate after all treatment modalities in Bowen's disease, related to both the ill-defined lateral margins and the frequent follicular involvement with the Bowen's process, prolonged treatment time is required for success with 5-FU. Treatment times employed were 4 to 12 weeks, with a median of 9 weeks. 5-FU concentration ranged from 1% to 3 % in propylene glycol. A 1% concentration of 5-FU was generally adequate on the face, except for occasional recalcitrant areas, such as the nose and eyebrow. A concentration of 2.5% to 3.0% was usually necessary for treatment of Bowen's disease on the other body areas.