Objective : Recent studies have been reported about the roles of estrogen receptor(ER), progesterone receptor(PR) and p53 in development of pelvic organ prolapse(POP). Pathogenesis of stress urinary incontinence(SUI) is known to be related to that of POP in weakness of pelvic support. So, this study was done to assess the relationship between ER, PR, p53 and development of SUI, thus to elucidate the biomolecular pathophysiology of SUI. Materials and Methods : Periurethral fascia was obtained from 4 SUI patients confirmed by urodynamic study and 10 without SUI visiting the department of Obstetrics and gynecology, severance hospital, Seoul, Korea. Relative protein level of ER, PR and p53 in periurethral fascia were obtained by western blot analysis and densitometry. Mann-Whiney U test and Fisher?s exact test were used for statistical analysis.(p<0.05) Results : The mean age and the number of vaginal delivery was significantly higher in study group.(62.5(8.1yrs vs 47.1(3.9yrs, p=0.032) ; 4.8(3.1 vs 1.8(0.9, p=0.032) There was no significant difference in body mass index(23.5(2.0 vs 25.1(3.7, p=0.396), ER(0.35(021 vs 1.80(1.03, p=0.017) and p53(1.30(0.84 vs 4.74(2.38, p=0.005) were significantly lower in study group. But there was no significant difference in PR(0.54(0.30 vs 0.35(0.41, p=0.564). Conclusion : p53 and ER were significant lower in study group. Our results suggest that p53 and ER might be the important factors in development of SUI. And further prospective studies about the association of ER, p53 and SUI would be needed to elucidate the molecular pathogenesis of SUI.