In considering the effects of chemotherapy on tuberculous infections of the urinary tract, the nature of the lesion responsible for -the infection must be borne in 'mind. A tubercle positive urine denotes the presence of a kidney focus or foci whence the organisms emanate. It follows that the aim of chemotherapy when employed for the treatment of this disease is not merely to render the urine tubercle negative; the objective must be the healing of the diseased kidney which otherwise will continue to act as a source of infection. Renal tuberculous lesions are encountered in infinite variety, from microscopic symptomless foci to solitary or multiple, ulcerative or caseo-cavernous excavations, which may ultimately riddle the organ. There may be clinical involvement of both kidneys, the disease in that event usually being more advanced on one side. A factor of fundamental importance in. its bearing on treatment is that renal tuberculosis is not a local disease, but is a blood-borne focal manifestation of a systemic infection generally commencing in the chest, less often in the gastro-intestinal tract. The extraurinary lesions may or may not be clinically active when the renal disease is recognized. Streptomycin is regarded as the most potent antibiotic that is at present available for the control of urinary tuberculosis, ant[ the main purpose of this article is to indicate what may be expected from its employment in this connection. The results obtained at Robroyston Hospital, where a controlled trial, which commenced three years ago under the auspices of the Tuberculosis Research Unit of the Medical Research Council and still continues, provide the source of the information that follows.