It is not infrequently reported that there appears the hyperplasia of parathyroid gland on the various diseases, however, that of the kidney-disease is very scarecely found in the literature, and especially its histological investigation is almost rare. On autopsy, 81 parathyroid glands which were obtained from 24 cases of serious chronic kidney diseases (age, from 9 to 80) and 154 parathyroid glands, from 62 cases of various diseases, excluding the above disease, (age, from 6 to 78), as control, were investigated by author and the result is as follows:- 1) Comparing the average of both the weight and the total amount of the three dimensions of parathyroid gland on the kidneydisease and its control, the former's average weight of parathyroid gland is estimated 94.4mg. and the latter, 67.0mg. and the total amount of the three dimensions on the kidney-disease is average 202.2cm and its contral, 100.6cm. 2) The parathyroid gland of the kidney-disease is uniformly rich of compact structure, and the incr ase of the interstitial connective tissue or the lipomatosis is not nearly recognized or scanty. On the main cells, the dark-main-cells decrease remarkably, on the contrary, the light-main-cells increase enormously and such occupy three quarters of the total cases. The most of the light-main-cell swell moderately or are enlarged remarkably and the hyperplasia or the adenomatous proliferation is also seen. The majority of the cases show a little or no more oxyophile cell, and it ersists isolately or scatteredly. The colloid decreases. In the parathyroid gland of the control, the dark-main-cells appear remarkably and the light-main-cells are vice versa. Mostly, the oxyophile cells appear a little but they appear moderately in 4 cases of the control and very remarkably in a case 3) The hypertrophy, hyperplasia and the increase of the light-main-cell of parathyroid gland on the kidney-disease are considered to signify its hyperfunction by author. And this may be also considered a change which has a close-relation with the calciummetabolism-disturbance or the bone-system-pathogenesis as is hitherto reported by many authorities. 4) The parathyroid gland on the kidney-disease mostly shows hyperfunction.