Purpose <p>There are conflicting recommendations concerning the performance of a systematic urine culture (UC) prior to Bacillus Calmette Guerin (BCG) bladder instillations for non-muscle-invasive bladder tumor. The objective was to study the organizational impact of the UC performed before bladder instillations, defined as the number and proportion of BCG instillations postponed due to a positive urine culture result.</p> Methods <p>Induction BCG records in a single academic center between 2015 and 2020 were retrospectively reviewed. All patients had a UC prior to each instillation, treated if positive. Risk factors associated with the occurrence of a positive UC, an adverse event or postponement of instillation were studied.</p> Results <p>A total of 156 patients were included, among which 68.9% of patients had at least one risk factor of UTI and 33% of patients presented at least one positive UC at induction. During BCG induction, 76/909 (8.4%) urine cultures performed were positive and 33% of patients had at least one postponement of BCG instillation. There were 64 instillations postponed, caused by untreated positive urine culture for 40 (62.5%) and absence of urine culture performed for 6 (9.4%) In multivariate analysis, only the presence of lower urinary tract symptoms was significantly associated with a risk of positive UC.</p> Conclusion <p>Positive UC during BCG instillations is a frequent event and a source of disorganization in BCG induction, with possible oncological consequences. A strategy of performing UC only in selected patients, could facilitate proper BCG administration and avoid unreasonable use of antibiotics.</p>