The major indication for pancreas or islet transplantation is diabetes mellitus type I. This process has to supply the insulin necessity keeping glucose under control. We have studied isogenic islet transplantation on the rat (WAG-RT1u) liver. The method of isolation and purification of the islets obtained 2.834 +/- 551.64 islets with purity of 83 +/- 2.45%. Diabetes was induced by streptozotocin and seric glucose prior transplantation was 35 mmol/L. The islet transplantation of 2.834 +/- 551.64 islets in the rat liver has normalized glucose test from 9.62 +/- 2.65 mmol/L 10 days after transplantation to 7.43 +/- 0.27 mmol/L later in the follow-up (P < 0.05). The median survival time of the islets was 73 days. In conclusion both the method of isolation and purification of the islets and islet transplantation was effective in the control of the diabetes induced by streptozotocin with median survival time of both islet and rat more than 73 days when rats were sacrified.