Cancer of unknown primary (CUP) is 3–5% of all malignant tumors in adult. And then, adrenal carcinoma is very rare and almost half of it has distant metastasis. Adrenal carcinoma with distant metastasis is difficult to be operated and diagnosed. Therefore we experienced two autopsy cases of CUP that were treated as adrenal carcinoma. Case 1: A 77-year-old male saw a local doctor to complain stomachache. Abdominal CT scan revealed an 8 cm tumor on the left of ventral aorta. We did biopsy of abdominal subcutaneous nodules and diagnosed poorly differentiated adenocarcinoma. We did chemotherapy of CBDCA + PTX. However, it is not effective. He died 5 months after first visit. It was diagnosed as pancreas cancer by autopsy. Case2: A 68-year-old male saw a local doctor to complain fever and stomachache. Abdominal CT scan revealed a 10cm tumor on the left of kidney. We did fine-needle aspiration biopsy with EUS through the stomach wall and he was diagnosed as adenocarcinoma. However, we did not recognize a primary lesion. We did chemotherapy of CDDP + GEM. The treatment was temporarily effective, but he had a fever after two cycles of chemotherapy. The tumor was drastically enlarged and he died 3 months after first visit. It was diagnosed as adrenal cancer by autopsy.