PIP: Clinical presentations, laboratory features, and responses to therapy of 102 patients treated at an army medical center for genitourinary tuberculosis between January 1961 and September 1972 are described. During that time, a total of 3109 patients had been treated for tuberculosis of all types. The study group included 72 men aged 18-59 with a mean age of 29, and 31 women aged 17-66, with a mean age of 31. There was often a latent period of 20 years or more between infection with the tubercle bacillus and the expression of genitourinary tuberculosis. The principal means of diagnosis was isolation of Mycobacterium tuberculosis from urine, obtained in 80%, or sputum, obtained in 38%. M. tuberculosis was not cultured in 13 patients. In patients with negative cultures, diagnosis was made by combinations of positive tuberculin skin test, caseating granulomata on biopsy, characteristic changes in the excretory urogram, characteristic bladder lesions on cystoscopy, and the presence of sterile pyuria or microscopic hematuria. A wide variety of signs and symptoms were encountered as was a high frequency of involvement of other organ systems. The most common laboratory abnormalities were pyuria, albuminuria, and hematuria. 75% of patients had an abnormal chest roentgenogram on admission. 88% of patients tested had positive skin tests and 63% tested had abnormal excretory urography. 16% showed renal calcification. Only 1 nephrectomy was done in the latter 5 years of the study, for hypertension. 2 women and 6 men had hypertension, but 1 woman and 2 men had nontuberculous renal disease which could have caused the hypertension. The evidence from the series is that infectivity of genitourinary tuberculosis is low. There was only 1 initial treatment failure, in a 47-year old man with active pulmonary and renal tuberculosis caused by an isoniazid-resistant organism. 2 men, only 1 of whom had had genitourinary disease originally, had recurrences of tuberculous disease after prematurely discontinuing medication.