Intravesical chemotherapy after transurethral resection of a bladdertumour (TURBT) has been observed to significantly decreaserecurrence rates compared to TURBT alone. Though immediatepostoperative intravesical treatment with chemotherapeutic agentsafter transurethral resection for superficial bladder carcinoma isgenerally considered a safe and effective adjunctive therapy indecreasing recurrence rates, its instillation is not always completelyinnocuous. Lately, a more serious complication of bladderperforation associated with immediate instillation of intravesicalmitomycin C (MMC) after TURBT was reported. We reportour own experience of a male patient with bladder perforationafter an early instillation of a single dose of MMC. In this case,systemic toxicity occurred which required intensive care aftersurgical repair.