A 36-year-old Korean woman had had a flesh-colored, indurated plaque with pruritus on the labium majora for five years. The lesion was not found in association with hyperpigmented or hypertrichotic patches. Results of biopsy specimens showed an excess of haphazardly oriented smooth-muscle bundles in the mid to lower dermis with an unremarkable overlying epidermis. Our diagnosis was an acquired smooth-muscle hamartoma in the vulva. Although there have been previously reported cases of acquired smooth-muscle hamartoma, this was the first reported case in the vulva. We also describe the characteristics differing between our case and the six previously reported ones.