Hepatic regeneration in alloxan-induced diabetic rats that underwent a 70% hepatectomy was compared to that of a series of non-treated rats. In diabetic rats, hepatic regeneration is lower and the liver reaches only 70% of the original weight ten days after hepatectomy. Analytical studies in these rats show a diminution of insulin and glucagon. Hepatic microcirculation as shown by measurements of CLV-CLV and CLV area undergoes changes which evolve at a different rate in the central and peripheral zones of the liver. These findings as well as the diminished hepatic regeneration may be attributed to the diminution of the insulin and glucagon values. Insulin and glucagon may be responsible for hepatic regeneration.