The distribution of immunoglobulins G, M and A in the small intestine of colostrum fed calves was monitored using immunofluorescent techniques. Colostral immunoglobulins were located in villous region of the small intestine where they were found either in the lamina propria, in the epithelial cells or on the mucosal surface of the epithelial cells. The distribution varied according to the age of calf examined. In very young calves, the villous epithelial cells were seen to be absorbing immunoglobulin of all 3 classes, whereas in 4 day old calves, the epithelial cells were generally devoid of immunoglobulin. In unsuckled calves, the intestinal immunoglobulins were synthesised in the Peyers patches and crypt region of the mucosa of the small intestine and immunoglobulin was found in the crypt epithelial cells and in plasma cells in the surrounding lamina propria.