Objective To assess the impact of adjuvant chemotherapy (ACH) on the survival of patients with pT3 urothelial carcinoma of the bladder (UCB) after radical cystectomy (RC). Methods We retrospectively analyzed the clinical and follow-up data of 223 UCB patients who underwent RC between January 2005 and June 2015. None of the patients received neoadjuvant chemotherapy. Of all the patients, 75 (33.6%) were diagnosed as pT3 cancer (including 32 pT3a and 43 pT3b patients). The follow-up data were up to June 2015. Kaplan-Meier method with log-rank test was used to estimate and compare overall survival (OS) and cancer-specific survival (CSS) between groups. Multivariate Cox proportional hazard models were used to identify predictors of OS and CSS. Results The short-term total effective rate of gemcitabine and cisplatin assisted chemotherapy in the treatment of pT3 UCB was 60.0%. Five-year OS rate (47.9%vs. 43.3%) and CSS rate (57.4%vs. 57.6%) were similar in the pT3a and pT3b groups (P=0.682 and 0.796, respectively). In pT3 patients, adjuvant chemotherapy was an independent predictor for OS (P=0.032). On multivariate analysis, according to the pT3 sub-stage, ACH was significantly associated with improved OS [hazard ratio (HR) =0.37; 95% confidence interval (CI) (0.15, 0.68),P=0.006] and CSS [HR=0.34, 95%CI (0.12, 0.86),P=0.022] in the pT3b group only. Conclusion Because pT3b cancer is characterized by macroscopic peri-vesical tissue invasion, patients may obtain an OS benefit from the administration of adjuvant chemotherapy.