The occurrence of abomasal displacement in Tokachi Shimizu Cho, Hokkaido, Japan has been surveyed in relation to milk production from 1979 to 1986. In 1983 when dairy cows produced over 5.000kg of milk yield per year. the occurrence rate of abomasal displacement increased over 1%. Thereafter, the occurrence rate increased markedly as the milk production approached 6.000kg. In order to increase the number of cows which can be surgically corrected, a special ambulatory vehicle for surgery was designed. Since more cows were surgically corrected. there was a subsequent decrease in the culling rate of cows with abomasal displacement. The present survey indicated that the occurrence rate of abomasal displacement was closely related to milk production, and that surgical correction was a very effective method to treat this condition.