We present herein an extremely rare case of metastasis from a gastric carcinoma to the mesocolon. A 71-year-old woman underwent a laparotomy for gastric cancer with an intra-abdominal mass. Her serum alpha-fetoprotein level was very high at 3,560 ng/ml. The abdominal mass was subsequently revealed to be a metastatic tumor of the transverse mesocolon derived from an alpha-fetoprotein-producing gastric carcinoma, but no other metastatic focus was found. An immunohistochemical study revealed alpha-fetoprotein-positive cells in both lesions. The serum alpha-fetoprotein level became normal after the operation which was followed by a course of chemotherapy, and no recurrence has been observed thus far in 6 months of follow up.