Mucosal cellular populations and glandular thickness in the corpus of the canine stomach was assessed in 30 dogs. The average number of mucous neck cells per “swath” of full thickness mucosa over a width of 0.223 mm was 41 (S.E. ± 2.09), of parietal cells, 95 (S.E. ± 8.71), of chief cells 205 (S.E. ± 12.63). The average glandular thickness was 557 μ (S.E. ± 24.71). The distribution of cells in the stomachs of four additional dogs was determined. More mucous neck cells were noted in the glands of the juxta‐antral and cardiac zones than in those of the corpus. Few parietal and chief cells were noted in the cardiac zone. In the corpus, however, these cells were abundant and evenly distributed. The data presented permit calculation of the total gastric mucosal cellular population of the stomach from an “average” 15 kg dog. The acid‐pepsin secreting area has a volume of 35 cm3, and therefore contains 4.3× 108 parietal cells, 7.2 × 108 chief cells, and 1.4 × 108 mucous neck cells.