We report a case of synchronous double primary vulvar cancer and renal cell carcinoma. Kidney mass was incidentally detected during preoperative evaluation of vulvar cancer, and was finally confirmed as a renal cell carcinoma. Although the initial result of 18F-fluorodeoxyglucose positron emission tomography was negative for a renal malignancy, nephrectomy was performed under the radiological and urologic impression of renal cell carcinoma which was supported by computerized tomography findings. Histological analysis finally confirmed a renal cell carcinoma. This is the first case report of synchronous double primary vulvar cancer and renal cell carcinoma, which emphasizes multidisciplinary approach to unexpected lesions when the clinical experience of one specialist is limited.