Introduction: The endoscopic resection of large and bulky bladder cancers represents a challenge. To reduce the tumor and make it more easy to resect, we used neoadjuvant short and intensive intravesical mitomycin (MMC) therapy. Methods: Patients with large bladder tumors were evaluated for this study. At cystoscopy, the surgeon evaluated the feasibility of complete resection. In patients where this was not possible, biopsies from the tumor, bladder mucosa, and prostatic urethra were taken. These patients then underwent a short and intensive cytoreductive schedule of intravesical MMC. This was then followed by TUR-BT. Results: Fifteen patients were included in our study. The mean age was 74 years (range: 56–82; SD ±6 years). Mean tumor size was 51 mm (range: 35–65; SD ±8 mm). After neoadjuvant treatment, complete resection was then feasible in all patients. The mean tumor volume after the chemo-resection had reduced to 34 mm (range: 10–50; SD ±13 mm). No adverse effects were reported. Conclusion: Intravesical cytoreductive neoadjuvant MMC as an initial treatment of large NMIBC can be considered safe, effective, and feasible.