The prevalence of prostatic cysts was evaluated in 85 adult, male dogs weighing more than 16 kg which were admitted for problems unrelated to the prostate gland. Urine culture and prostatic evaluation by ultrasonography were performed in all dogs. Prostatic cysts were identified in 12 (14%) of the 85 dogs. Cultures of prostatic cysts were positive in five (42%) of the 12 dogs. Nonclinical, aerobic bacteriuria was documented in 9% of the study population. Urine cultures correlated with prostatic cyst cultures in four of the five dogs that had positive prostatic cyst cultures. Results of this study indicate that the prevalence of prostatic cysts in adult, intact male dogs is approximately 14% and that approximately 42% are infected with bacteria.