Four techniques for segmental pancreatic transplantation were used sequentially in rats. The success rate and the incidence and type of technical complications that developed in each group of recipients were determined and attempts were made to improve the microsurgical technique. A strict comparison of the relative merits of the four different techniques was not made, but rather the development of an approach to an original technique that resulted in a high success is rate presented. The various modifications and details of this experience are documented. The various complications, each of which results in a typical postoperative pattern of weight and plasma glucose changes and each of which is preventable by the use of proper microsurgical techniques, are also analyzed.