Intravesical chemotherapy after transurethral resection of a bladder tumour (TURBT) has been observed to significantly decrease recurrence rates compared to TURBT alone. Though immediate postoperative intravesical treatment with chemotherapeutic agents after transurethral resection for superficial bladder carcinoma is generally considered a safe and effective adjunctive therapy in decreasing recurrence rates, its instillation is not always completely innocuous. Lately, a more serious complication of bladder perforation associated with immediate instillation of intravesical mitomycin C (MMC) after TURBT was reported. We report our own experience of a male patient with bladder perforation after an early instillation of a single dose of MMC. In this case, systemic toxicity occurred which required intensive care after surgical repair.