Bowen's disease is a special form of squamous cell carcinoma in situ that usually develops in photoexposed areas of skin. The treatment of choice is surgery. Less frequently, it may appear in other locations such as the nails, glans penis, intertriginous areas and the perianal region, where conventional treatment may be complicated. We contribute a new case of perianal Bowen's disease, which responded to treatment with imiquimod with no evidence of clinical recurrence after 3 years of follow up. Imiquimod appears to be a therapeutic alternative for perianal Bowen's disease, which seems to have a particular tendency to recur in this location where surgery may also be complicated.