Aim The aim of this study was to compare the patients with and without histologically proven prostate carcinoma who underwent radical cystectomy for muscle invasive bladder cancer in terms of bladder tumor properties and survival rates. Material and Methods A total of 149 male patients who had undergone radical cystectomy and urinary diversion between 1994-2007. in our institution were included in our study. Medical records of the patients were analyzed retrospectively. Fourteen (9.3%) patients had co-existing prostate carcinoma, while remaining 135 (90.7%) did not. The two groups were compared to each other with respect to the oncological properties of the bladder tumors (stage and grade) and disease specific mortality rates. Results The mean ages for the patients with and without co-existing prostate carcinoma were 64.2±8.4 and 57.7±10.8, respectively. There was a significant difference between the ages of the two groups (p=0.029). There were not any significant differences among the two groups regarding bladder cancer pathological stage (p=0.199) and grade (p=0.544). The disease specific survival rates of the two groups for three years were: 61.76% and 81.82% for the patients with and without coexisting prostate carcinoma respectively. No significant difference was observed between the disease specific survival rates of the two groups (p=0.325). Conclusion The co-existing prostate carcinoma had no significant effect on tumor stage, grade and disease specific survival rates of patients who underwent radical cystectomy for muscle invasive bladder cancer.