Bcell replacement, either by the intact whole pancreas or by an isolated pancreas islet, has become a clinical option to be considered in the treatment of patients with type 1 insulin-dependent diabetes mellitus or some of type 2 diabetes. Between the two treatment options, the pancreas transplantation has been shown to be very effective at maintaining an euglycemic state for a sustained period of time providing the recipient with a normal life. The graft survival has been improved due to a current combination of immunosuppressants, refined surgical techniques, and a better postoperative patient care. However, it is associated with a risk of surgical and postoperative complications. The islet transplantation has been considered to be an attractive treatment modality as a less invasive and easily applicable procedure in lieu of whole organ pancreas transplantation. In spite of its many advantages, the islet transplantation has not always achieved the sustained level of normoglycemia without insulin. A poor early or long term graft survival is considered to be caused by inconsistent low islet yield, initial considerable amount of graft loss during engraftment period, rejection of islet in hepatic environment, and absence of monitoring tool for islet graft function. Although current clinical reports have led to a promising result, further improvements are needed to get the long term successful results. Now the current status of pancreas and islet transplantations is reviewed and perspectives of these treatments are discussed.