Seven pancreases from nondiabetic autopsy cases were submitted to morphometrical analysis of the islets of Langerhans as a preliminary investigation of the diabetic pancreas. The pancreatic islets were approximately simulated by spheres of different sizes randomly dispersed in the three-dimensional space; thereon the parameters of Weibull function assumed for the distribution of islet radii were estimated stereologically from chord length measurements on histologic sections taken from different portions of the pancreas. By means of the estimated parameters topographical comparison of the number, volume, mean radius and size distribution of islets in a unit volume were performed. This islet distribution appeared to change the pattern gradually according to the position from the pancreatic head to the tail: the head was characterized by abundance of small islets that corresponded to a slightly higher islet population threat, whereas the tail by moderate increase of larger islets that caused a steep increase of islet volume here. To estimate parameters for the whole pancreas a histologic section from a range between the midposition of the pancreas and the one-fourth position from the splenic end was regarded to be a fairly good representative.