Abstract: Histogenesis of intestinal metaplasia(IM) of gastric mucosa was studied in Wistar rats treated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and ranitidine.IM was found from 9 weeks after the beginning of MNNG and ranitidine administration.Metaplastic glands appeared only in neck region before 12 weeks.and followed upwards and downwards at 14 and 16 weeks.IM in the different levels of the gastric mucusa,mainly confined to the lower third of thes mucosa was observed after 18 weeks.These findings suggest that IM arise from the neek proliferative cell zone and then extend to the surface and bottom of the gastric mucosa.