1 - The AA. observed a case of gonococcal infection of kidney which they report with the necessary details, both from the clinico-surgical and bacteriological standpoints. 2 - In perusing the bibliography on the matter, they verified that gonococcal infections of kidney are rare, and very rare those which present proofs of thorough bacteriological identification of the gonococcus, such as was furnished in the present case, which should occupy the 15th place since the discovery of the germ by Neisser, 59 years ago. 3 - In the bacterioscopical examination of the urinary sediment and of the pus from the kidney the bacteriological proofs are constituted by the characteristic features of the colonies and cultures, followed by examinations of the smears, by fermentation tests for glucose and maltose, by sero-agglutination and gono-fixation. All tests were positive for gonococcus. 4 - The kidney does not favour the proliferation of the gonococcus, either thanks to the nature of its epithelium, or thanks to the secretion of substances which prevent the development of the gonococcus, or thanks to any other cause. Taking into consideration the frequency of gonococcal infections of the lower urinary apparatus, it was to be expected that also the upper one should be attained in a great deal of cases. 5 - As to the causes which predispose to such a secondary attack proceeding by the way of blood, of lymphatic current or by contiguity, uhle quotes the following: 1º - Congenital disorders, obstruction changes, mainly of the ureter; 2º - Calculi, tumors, etc.; 3º - Traumatisms followed by rupture and hemorrhage; and 4º - Previous pathological conditions not yet demonstrated. our case fits into the 2º paragraph. The kidney presented a malignant tumor and contained numberless calculi. 6 - After the removal of the kidney by surgical intervention, which passed of without accidents, the patient soon began to improve being discharged on cure from the Hospital. Up to the present date, nothing occurred which might arouse the suspicion upon the development of any metastasis of the tumor. By the way, the operation had been indicated by virtue of the infectious condition, prior to the detection of the carcinoma. 7 - Another interesting fact to be recorded is also that the lower urinary apparatus, in spite of the kidney being attacked by gonococcus, showed nothing in this respect, either before the operation, or after the patient's dismissal. 8 - As may be seen from the works of the centres where investigations are systematically performed, cases such as the present one although rare have to appear again at times, and therefore the bacteriological examination of cases of suppurating renal infections is always to be recommended.