The morphology and distribution of granulated metrial gland cells and of interstitial trophoblast cells in the uterine wall was studied in the first half of pregnancy in the bank vole, Clethrionomys glareolus. The morphology and distribution of granulated metrial gland cells was generally similar to that found in other members of the Rodentia, although they were absent from the walls of the arterial vessels passing through the decidua basalis. Interstitial trophoblast invaded the decidualising endometrium mesometrial to, and antimesometrial to, the implanted embryos. There was no apparent spatiotemporal relationship between the distribution of granulated metrial gland cells and interstitial trophoblast cells.