Introduction: We aimed to test the hypothesis that the immune-modulatory effect of statins may improve survival outcomes in patients with non-muscle invasive bladder cancer (NMIBC). We focused on a cohort of patients diagnosed with high risk NMIBC, that were treated with intravesical BCG immunotherapy.Patients And Methods: We included patients at first diagnosis of T1 high grade NMIBC after transurethral resection of bladder (TURB). All procedures were performed at 18 different tertiary institutions between January 2002 and December 2012. Univariable and multivariable models were used to test differences in terms of residual tumour, disease recurrence, disease progression and overall mortality (OM) rates.Results: Overall, 1510 patients with T1 high grade NMIBC at TURB were included in our analyses. Of these, 402 (26.6%) were statin users. At multivariable analysis, statin use was associated with a higher rates of high grade BC at re-TURB (OR: 1.37, 95%CI: 1.04-1.78; p=0.022), while at follow-up it was not independently associated with OM (HR: 0.71, 95%CI: 0.50-1.03; p=0.068) and disease progression rates (HR: 0.97, 95%CI: 0.79-1.19; p=0.753). Conversely, statin use has been shown to be independently associated with a lower risk of recurrence (HR:0.80, 95%CI: 0.67-0.95; p=0.009). The median recurrence-free survival was 47 (95%CI 40-49) months for those classified as non-statin users vs. 53 (95%CI 48-68) months in those classified as statin users.Conclusions: Statin daily intake do not compromise oncological outcomes in high risk NMIBC patients treated with BCG. Moreover, statin may have a beneficial effect on recurrence rates in this cohort of patients.