A refined foraminiferal biostratigraphy of the Middle Permian Kamiyasse Formation in the Kamiyasse area north of Kesennuma, Southern Kitakami Terrane, NE Japan, is presented. Based on the stratigraphic distribution of schwagerinid and neoschwagerinid fusulinoideans, the Kamiyasse Formation, equivalent to the Kanokura Formation in the type area (Setamai-Yahagi area), is subdivided into the Monodiexodina sutchanica, Parafusulina motoyoshiensis and Lepidolina shiraiwensis Zone in ascending order, all of which appear to correspond to the Midian (latest Wordian to Capitanian) in age. The M. sutchanica Zone is here defined as integrated with cross-stratified sandstone beds in the bottom of the formation, and this zone is no longer equivalent to the previously defined M. matsubaishi (junior synonym of M. sutchanica) Zone in the Iwaizaki Limestone and the Kanokura Formation of the type area. The other two zones are defined with the first occurrences of the zonal species. Foraminifers are highly diverse along the stratigraphic interval between the Parafusulina motoyoshiensis and Lepidolina shiraiwensis Zones. Fifty-seven species belonging to 42 genera of foraminifers are identified. Nineteen species among them are systematically described and discussed, including the following three species: Baisalina rikuzenensis sp. nov., whose middle and later whorls are subdivided into more than fifteen chamberlets by septal protrusions; Wutuella sp., previously misidentified as “Cancellina” sp.; and Septagathammina sp., exclusively known from South China.