Objective:The aim of our study was to clarify the clinicopathological factors affecting the outcome of T1G3 urothelial carcinoma of the bladder.Methods:We retrospectively reviewed 62 cases of T1G3 bladder cancer treated with transuretheral resection of bladder toumor (TURBT) followed by intravesical instillation between 1997 and 2009.Cumulative survival was analyzed by Kaplan-Meier method.Cox regression was used for univariate and multivariate analysis.Log-rank method was used for the significance test.The statistical difference was accepted when the P value was lower than 0.05.Results:Median follow-up period was 40 months (6-140 months).Forty-one cases of intravesical recurrence (66%) were observed during follow-up.Two-and 5-year recurrence-free survival rates were 43.4% and 35.1%.Fourteen cases of progression (23%) were observed during the follow-up period.Two-and 5-year progression-free survival rates were 86.4% and 83.5%,respectively.Significant factors for tumor recurrence and progression were analyzed by Cox regression.Tumor multiplicity (RR=2.250),size (RR=1.039) and history of recurrence (RR=2.162) were significantly correlated with recurrence and tumor multiplicity (RR=3.695) was significantly correlated with progression on multivariate analysis.Conclusion:Tumor multiplicity,size,history of recurrence were correlated with recurrence and tumor multiplicity was significantly correlated with progression.Tumor multiplicity,size and history of recurrence should be taken into account when we make therapy strategies for T1G3 urothelial carcinoma of the bladder. Objective: The aim of our study was to clarify the clinicopathological factors affecting the outcome of T1G3 urothelial carcinoma of the bladder. Methods: We retrospectively reviewed 62 cases of T1G3 bladder cancer treated with transuretural resection of bladder toumor (TURBT) followed by intravesical instillation between 1997 and 2009. Cumulative survival was analyzed by Kaplan-Meier method. Cox regression was used for univariate and multivariate analysis. Log-rank method was used for the significance test. Statistical difference was accepted when the P value was lower than 0.05. Results : Median follow-up period was 40 months (6-140 months). Forty-one cases of intravesical recurrence (66%) were observed during follow-up. Two-and 5-year recurrence-free survival rates were 43.4% and 35.1 % .Fourteen cases of progression (23%) were observed during the follow-up period.Two-and 5-year progression-free survival rates were 86.4% and 83.5%, respectively. Significant factors for tumor recurrence and pro (RR = 2.250), size (RR = 1.039) and history of recurrence (RR = 2.162) were significantly correlated with recurrence and tumor multiplicity (RR = 3.695) was significantly correlated with progression on multivariate analysis.Conclusion: Tumor multiplicity, size, history of recurrence were correlated with recurrence and tumor multiplicity was significantly correlated with progression .umor multiplicity, size and history of recurrence should be taken into account when we make therapy strategies for T1G3 urothelial carcinoma of the bladder .