We report the case of a 33 year old female presenting with an upper pole renal mass suggestive of renal cell carcinoma which in the pathological specimen resulted to be a retained surgical gauze.The case of a female patient with history of previous nephrolithotomy 5 years before who presented with flank pain. CT-scan and ultrasound were suggestive of malignant renal mass.A retained surgical gauze should always be suspected in all patient with an abdominal mass and with history of previous surgery close to the area of the lesion without caring the time lapsed between surgery and the discovery.