Adrenocortical carcinoma is a rare malignancy in adolescents and young adults. The prognosis of unresectable/metastatic adrenocortical carcinoma remains very poor because the rarity of the tumor has made it difficult to establish treatment guidelines, and diagnosis and the resultant treatment can be greatly delayed. We treated a 24-year-old woman who was diagnosed with adrenocortical carcinoma of the right adrenal gland which extended to the inferior vena cava. Although she underwent surgical resection of the extensive tumor as the primary treatment, the disease recurred in the lung and liver as multiple metastases shortly after surgery. She received intensive multimodality therapy, including chemotherapy with paclitaxel, ifosfamide, and cisplatin (TIP regimen), embolization of the feeding arteries, and proton irradiation for the liver mass. Finally, she underwent reduced-intensity allogeneic hematopoietic stem cell transplantation from an HLA 1-locus-mismatched sibling donor. A prolonged survival of 39 months after the onset of the disease was achieved. Although this experience is limited, we suggest that TIP chemotherapy was effective for adrenocortical carcinoma, and a graft-versus-tumor effect after reduced-intensity stem cell transplantation may have contributed to the prolonged survival.