To determine whether the dysfunction of p53 caused either by mutation of the p53 gene itself or by binding to E6 protein of oncogenic HPVs is involved in the transitional cell carcinomas (TCCs) of the bladder, we analyzed 23 TCCs of the bladder. DNA was extracted from each paraffin embedded tissue of TCCs of bladder and polymerase chain reaction (PCR)/single strand conformation polymorphism (SSCP) analysis were performed to screen mutations in p53 tumor suppressor gene, then PCR/dot blot hybridization were performed to detect infection of HPVs. We found that p53 gene mutation was found in 3 cases and oncogenic HPV infection was detected in 8 cases and thus, the overall incidence of possible p53 dysfunction was 47.8% on DNA analysis (If the results of immunohistochemistry to detect overexpression of p53 protein were included, the incidence was 60.9%). Therefore, we concluded that dysfunction of p53 plays a major role in the development of TCCs of bladder in Korean patients.