To evaluate the prognostic value of concomitant seminal vesicle invasion (cSVI) in patients with urothelial carcinoma of the bladder (UCB) and contiguous prostatic stromal infiltration in a large cystectomy series. A total of 385 patients with UCB and contiguous prostatic infiltration comprised our study. Patients were divided in two groups according to cSVI. Median follow-up was 36 months (interquartile range 11–74); the primary end point was cancer-specific mortality. The prognostic impact of cSVI was evaluated using multivariable Cox regression analysis. The predictive accuracy was assessed by a receiver operating characteristic analysis. A total of 229 patients (59.5 %) without cSVI comprised group A, and 156 patients (40.5 %) with cSVI comprised group B. Positive lymph nodes (63 vs. 44 %, p