A 75-year-old man presented with a left inguinal mass two months after surgery for ascending colon cancer. Physical examination revealed a solid mass in the left inguinal area. High orchiectomy was performed under the diagnosis of spermatic cord tumor. Gross examination of the specimen revealed a 5.0 X 3.2 X 3.0 cm tumor in the spermatic cord. Pathological examination of the tumor was reported as poorly differentiated adenocarcinoma with features similar to those of previously resected colon cancer. He developed peritonitis carcinomatosa and died 6 months after left orchiectomy. To our knowledge, a metastatic tumor of the spermatic cord from colon or rectal cancer is rare. As previously reported, the prognosis of this case was also poor.