We present a case of Bowen's disease showing a clinical tendency toward spontaneous regression. The patient, a healthy 86-year-old woman, complained that erythema had appeared on her left forearm two years earlier and had gradually enlarged. At the first examination, we observed a well-demarcated, 4 x 3 cm, erythematous plaque, partically covered with crusting and erosions near the wrist. Diagnosis of Bowen's disease was confirmed by a biopsy. Since the patient refused surgery and also discontinued hyperthermic treatment with disposable chemical pocket warmers after a brief trial, we decided to continue the observation of disease progression without any treatment. Two years after the initial visit, the lesion showed a clinical tendency toward spontaneous regression, with a fine erythematous plaque that showed the obscurely demarcated border of the lesion. After three years, although the patient exhibited a similar symptomatic improvement, a skin biopsy showed a few residual tumor cells. At the patient's request, we chose to observe the progress of the lesion. We review the literature of cases of Bowen's disease that have shown a similar tendency toward spontaneous regression, which have been rare.