A case of right thoracic kidney with simple renal cyst is reported. A 67-year-old man was pointed out to have an abnormal shadow in the right lower lung field of chest X-ray film. He was asymptomatic. Laboratory test was normal. Computed tomography and excretory urography confirmed the right thoracic kidney with a simple cyst. Adrenal scintigraphy revealed a high ectopic adrenal gland with right thoracic kidney. Since he was asymptomatic, treatment was not required. High ectopic kidney is extremely rare and 74 cases have been reported in the domestic literature in Japan. Thoracic kidney should be considered as one of differential diagnoses of abnormal mediastinal shadow.