This study was conducted to localize estrogen receptor beta (ER beta) in the rat urinary bladder respect to gender. The bladder dome and trigone of 16 Sprague Dawley rats (Male: 8, Female: 8) were evaluated utilizing the reverse transcriptase-polymerase chain reaction technique (RT-PCR) to detect ER beta signal. Chi square test was used for statistical analysis. ER beta was present in the bladder of 13 rats and absent in 3. The side of expression was bladder trigfone in 13 rats and besides ER beta (M: 1, F: 2) was also present in the bladder dome of 3. The relationship between the distribution of ER beta in the bladder and gender was not different. ER beta is present in the bladder trigone of rats independent of gender. Estrogen action in the bladder trigone is also important in males besides females.