<i>Objective:</i> The aim of this work was to verify the tolerability and the preliminary clinical results of intensive intravesical instillations of a mitomycin C (MMC) regimen. <i>Patients and Methods:</i> From September 2007 to November 2009, 40 consecutive evaluable patients with pathologically confirmed intermediate-risk non-muscle-invasive bladder cancer (NMIBC) were enrolled after complete transurethral resection of all visible tumors. The mean age of the patients was 64.5 years. 40 mg MMC diluted in 50 ml of saline was instilled in the bladder three times a week for 2 weeks. The median follow-up was 9 months. <i>Results:</i> All patients fulfilled the scheduled treatment. The local adverse events seen were negligible, while no significant deviation from normal values was observed in blood counts for each patient. Twenty-three of 40 patients (57.5%) showed negative at the cystoscopic control which was performed every 3 months with normal spontaneous and washing cytological exams. <i>Conclusion:</i> MMC is a well-known chemotherapeutic agent for the intravesical therapy of NMIBC. With a view to improving its results, we changed the frequency and intensity of the instillations. No significant local or systemic toxicity was reported. Intensive intravesical instilllations of MMC might become a tool in the management of NMIBC.