The effect of splenectomy on wound healing has been studied in standard laparotomy wounds in rats. Significant differences in wound histology, fibroblastic labelling indices, bursting pressure, and IgM levels were found between chronically asplenic rats and controls. Autotransplantation of the spleen conferred some increase to wound strength. Acute asplenic rats have not demonstrated the same changes. It is concluded that the spleen influences wound healing probably through a fibroblastic stimulating mechanism.