A desmoplastic small round cell tumor (DSRCT) is a rare, aggressive mesenchymal neoplasm. Although a DSRCT can develop at various sites, the intraabdominal site is the most common location. These tumors are found most commonly among young adolescents and the prognosis is extremely poor. Multimodal treatment with surgery, chemotherapy and radiotherapy is very important for these rare cases, and this treatment can improve patient survival. In this report, we describe the case of an 8-year-old boy diagnosed with DSRCT located in the retroperitoneal space. The patient has undergone surgical resection and adjuvant chemoradiation therapy, and is currently alive without disease recurrence. Although a DSRCT can develop at various sites, the intraabdominal site is the most common location. These tumors are found most commonly among young adolescents and the prognosis is extremely poor Multimodal treatment with surgery, chemotherapy and radiotherapy is very important for these rare cases, and this treatment can improve patient survival. In this report, we describe the case of an 8-year-old boy diagnosed with DSRCT located in the retroperitoneal space. The patient has undergone surgical resection and adjuvant chemoradiation therapy, and is currently alive without disease recurrence.