Objective : The bladder trabeculation was known to the consequence of secondary change following hypertrophy of bladder muscle. This study was aimed to investigate the relationship between bladder trabeculation and urinary function, the stage of pelvic organ prolapse. Methods : The charts of 104 patients with the chief complaints of pelvic organ prolapse visited at Yonsei University Medical Center from Mar.1999 to Mar. 2003 and underwent cystocopy and urodynamic studies were reviewed retrospectively. 1)The patients were grouped to the differences of bladder trabeculation and compared by patients' age, incidence of detrusor instability, the stage and site of pelvic organ prolapse, the paremeters of urodynamic study-maximal voiding velocity(Qmax), intravesicular pressure(Pdet), the percent of residual urine volume(residual urine volume/voided urine volume), maximal capacity of bladder. 2)the differences of incidence of bladder trabeculation were estimated between doubtful bladder outlet obstructed patients and or not. The relationship of doutful bladder outlet obstruction and the existence of bladder trabeculation was evaluated. The t-test and k2 test were used for statistic analysis(p<0.05). Results : ⅠThere were significant differences in patients' age, stage of pelvic organ prolapse and maximal voiding velocity(respectively, p<0.05, p=0.023 and p<0.05). There were no significant differences in incidence of detrusor instability, site of pelvic organ prolapse, intravesicular pressure, the percent of residual urine volume and maximal capaicty(respectively, p=0.727, p=0.095, p=0.052, p=0.05 and p=0.402). The doubtful group for bladder outlet obstruction that Qmax was less than 12ml/sec and Pdet>20cmH2O Conclusion : There were more advanced stage of pelvic organ prolapse in patients' group with bladder trabeculation. In point that the incidence of bladder trabeculation was increased significantly in the group with suspicious bladder outlet obstruction.