A 74-year-old man with terminal chronic kidney disease, under hemodialysis and with residual diuresis, was admitted due to myalgia, arthralgia, fever and pyuria in the previous 10 days. The patient had a recent diagnosis of high-grade non-invasive bladder cancer and was doing weekly BCG intravesical administrations. The symptoms started three days before the fifth administration. He had done cefixime as an outpatient and started piperacillin-tazobactam on hospital admission, but the fever persisted, and there was no bacterial isolation in urine or blood culture. On the tenth and seventeenth day after the last BCG intravesical administration Mycobacterium bovis was still isolated in the urine culture. The diagnosis of BCGitis was made and treatment was started, with a good response. Forty days after the last administration and under treatment, the culture remained positive for Mycobacterium bovis in the urine. We raise the question about the safety of BCG administration in patients with residual diuresis.