The downward displacement in stomach cancer mortality among Japanese migrants to the United States and their descendants provides an opportunity to see whether the changes in risk can be associated with changes in customs, occupation or other environmental exposures traceable to migration. Case control studies in two prefectures of Japan and in Hawaii and California undertaken with this objective in mind are described. Some preliminary results from interviewing in Miyagi prefecture on the association of selected items of diet with stomach cancer are presented and discussed. References ArRD, 1., BENTALL, H.H., and RoBERTS, J. cer in Hawaii. Milit. Med. 131, 222-223 A.F ., A relationship between cancer of (1966). stomach and the ABO blood groups. Brit. SEGI, M., and KuRrHARA, M., Cancer mor med J. 1953 I, 799-801. tality for selected sites in 24 countries, BrLLINGTON, B.P., Gastric cancer-relation No. 3, (1960/61). Sendai, Japan, Tohoku ships between ABO bloodgroups, site and University School of Medicine 1964. epidemiology. Lancet 1956 II, 859-862. SMITH, R.L., Recorded and expected mor BucKWALTER, J.A., WoHLWEND, C.B., tality among J apanese of the United States CoLTER, D.C., TmRrcK, R.T., and and Hawaii, with special reference to can KNOWLER, L.A., The association of the cer.]. nat. Cancer lnst. 17, 459-473 ABO blood groups to gastric carcinoma. (1956).