Solitary fibrous tumor (SFT) is an unusual spindle cell neoplasm rarely described in the kidney. Usually occurring in the pleura, it has also been described in various extrapleural sites. We report a rare case of SFT of the kidney fortuitously found in a 55-year-old patient. The imaging features are illustrated. The definite diagnosis was made through histological and immunohistochemical study after radical nephrectomy.