BACKGROUND: Ganglioneuroma (GN) is a rare benign tumor arising from the neural crest cells. The reported incidence of GN is one per million population. As a primary retroperitoneal tumor, it constitutes only a small percentage of 0.72 to 1.6%. GN can arise de novo or as a result of maturation of a neuroblastoma either spontaneously or after chemotherapy. The most common location is the posterior paraspinal mediastinum, retroperitoneum, neck and adrenal gland. However, GN can potentially occur anywhere along the peripheral autonomic ganglion sites. Most ganglioneuromas are asymptomatic and found incidentally. CASE REPORT: We present a case of retroperitoneal ganglioneuroma that mimicked renal mass on imaging. The tumor was incidentally discovered during an abdominal ultrasound examination 43-year-old male patient without clinical symptoms. Complete surgical resection was subsequently performed and histopathological examination of the retroperitoneal mass revealed GN. CONCLUSIONS: Retroperitoneal ganglioneuroma is a rare bening tumor, generally asymptomatic, which grows slowly, and appears large when it is identified. Preoperative diagnosis can be challenging, particularly in asymptomatic case. Histopathological examination is currently the mainstay of diagnosis. In the case presented herein GN stricktly adjoined to the left kidney mimicking renal mass.