The present histological investigation showed that bilateral truncal vagotomy (with accompanying pyloroplasty) reduced the sulphomucin-containing cell population of the pyloric antral mucosa of the rat stomach. Although this did not reach statistical significance (95% confidence limits), study of the absolute distribution of the sulphomucin-containing cells showed that significantly fewer of these cells were situated in the basal third of the mucosa as a result of the operation. A study of the percentage distribution revealed that a much higher percentage of sulphomucin-containing cells was present in the middle third of the mucosa in vagotomized rats than in the corresponding regions of the control stomachs. Thus, vagotomy and pyloroplasty had effected a redistribution of the sulphomucin-containing cells in the pyloric antrum. The possible explanation and significance of this finding are discussed.