Because the etiopathogenesis of the Waldeyer's ring hypertrophy is not fully recognized, evaluation of adrenal cortex function in this disorders was made. Serum cortisol level was determined by sulfuric acid fluorescence under resting conditions and 3 hours after ACTH injection. Investigations were performed on 20 children, aged 5-9 years, in all of them a marked hypertrophy of palatine and pharyngeal tonsils was found. These children were divided into two groups, the first one included 11 children with frequent angina and the second group consisted of 9 children with serious difficulties in breathing, but without angina. In these groups serum cortisol levels were estimated before and 3-4 months post tonsilectomy or adenotomy. 11 healthy children of the similar age were included into a control group. It was found that in the first group (hypertrophy and frequent angina) initial resting and ACTH stimulated cortisol levels were statistically significantly higher than in the control group. In the same group 3-4 months post surgery serum cortisol levels were lower and similar to those found in control group. On the contrary, in children of the second group (hypertrophy without angina) the resting and ACTH stimulated serum cortisol levels were lower than in control group and these levels did not change 3-4 months after surgery.