Type 1 diabetes is an autoimmune disease in which the insulin-producing cells of the pancreas are destroyed. Complications that arise from type 1 diabetes include blindness, kidney failure and nerve damage. Current treatment is with daily insulin injections, although some may be eligible for a pancreas or islet transplant. However, this is usually reserve for those with end-stage kidney failure. Furthermore, there are not enough donors to meet this demand should every diabetic receive a pancreas or islet transplant. It is for this reason that alternative sources of insulin-producing cells must be considered as another form of treatment. In this book, the transplantation of insulin cells from the fetal pig pancreas is examined as an alternative therapy, with the use of the outbred pig as an animal model for type 1 diabetes. A historical perspective of diabetes is also discussed as well as the different types of anti-rejection drugs used and the mechanisms of graft rejection. Finally, the possibility of eliminating the need for anti-rejection drugs through the means of encapsulation, is explored.