The relationship between the degree of amyloidosis in pancreatic islet tissue and the frequency of islets containing amyloid was studied in an autopsy material. A very strong positive correlation was found between these two variables in both the head and the tail of the pancreas. There was also a positive correlation between the degree of amyloidosis in islets containing amyloid and their frequency. This may indicate that the deposition of amyloid in the islets of Langerhans is a continuous process affecting progressively increasing numbers of islets. It is probable that the amyloid formation in the islets is influenced by some factor or factors that affect the different islets to different degrees. It is conceivable that one such factor may be vascular changes. The strong correlation between the frequency of islets containing amyloid and the degree of amyloidosis can be utilized as a simple and rapid method of determining the latter.