The pancreas changes morphologically as well as functionally in aging, with the corresponding increase of abnormal glucose tolerance. In a few cases with a normal pattern, it is very interesting to investigate if the endocrine as well as the exocrine function is preserved. Endocrine and exocrine functions of the pancreas was therefore studied in the following three groups; the young, the aged with a normal pattern of the 100g glucose torelance test and the patients who with chronic pancreatitis. The combined stimulation test which was established as the strongest stimulation to B cells by Ryan et al. was conducted using 100g of glucose, 1mg of glucagon and 0.5g of tolubutamide. The pancreozymin secretion test was also conducted to examine the pancreatic exocrine secretion. Results are as follows. (1) With the 100g glucose torelance test, no significant difference was noted in the blood sugar and serum insulin level between the aged and the young. On the other hand, a marked hyperglycemia and a decline of serum insulin secretion were noted in the group of chronic pancreatitis. (2) With the combined stimulation test, a significant difference was noted between the aged and the young. In the young, the serum insulin (IRI) showed a sharp rise up to the maximal level in 35 minutes after the stimulation of glucagon and tolubutamide and then returned to the level before the stimulation in 90 minutes. In the aged, the IRI rose slowly after the stimulation up to the maximal level which was lower than that of the young and stayed there in 90 minutes. In the group of chronic pancreatitis, the maximal level was much lower with a rather mild response curve. On the other hand, blood sugar response curve showed a sharp rise and then a slow decline after the stimulation in the aged. In the group of chronic pancreatitis, hyperglycemia was noted throughout the whole course. ΔIRI/ΔBS showed significant differences among the three groups; the young 13.0, the aged 5.5 and the group of chronic pancreatitis 1.4. With the P-S test the pancreatic secretory volume, the maximal bicarbonate concentration and the total amylase excretion were equally diminished in the aged and furthermore, highly decreased in the group of chronic pancreatitis. In these three group, a positive significance was exhibited in the correlation between the maximal IRI and the total amylase output on the combined stimualtion test. Conclusion: In contrast to healthy young people, the aged with a normal pattern of glucose torelance test, reveales a decline of endocrine and exocrine secretion in response to the strongest stimulation to the pancreas. This seems to be an essential phenomenon with aging suggesting the functional decline of exocrine and endocrine secretion due to the deterioraive changes of pancreatic tissue occuring in the course of aging.