Abstract Aim: Surgical procedures using synthetic implants are currently considered as the most efficient therapy for stress urinary incontinence (SUI) and pelvic organ prolapse (POP). Insertion of the tape or mesh causes enhanced collagen synthesis that largely affects the biomechanical property of the implant. This process is significantly modulated by estrogens and improper wound healing and treatment failure may result in hypoestrogenism. The aim of the study was to assess the rate of collagen type III synthesis by pubocervical fascia fibroblasts cultured with polypropylene meshes in the presence of estrogens and tamoxifen. Material and Methods: Fibroblasts were obtained from pubo-cervical fascia sampled from a 52-year-old premenopausal woman who underwent surgical treatment for SUI and cultured with monofilament or multifilament polypropylene meshes in the presence of 17β-estradiol, estriol, daidzein or tamoxifen. The cultures were run for 216hr and the media were replaced every 72hr. N-terminal propeptide of type III procollagen (PIIINP) was used as a marker of collagen type III synthesis. Its concentration in the media was measured by radioimmunoassay. Pubocervical fascia fibroblast cultured with monofilament or multifilament meshes are capable of collagen type III synthesis. Following treatment with estradiol or tamoxifen, the highest PIIINP concentrations were observed after 72hr, whereas in case of estriol, daidzein or no treatment after 144hr of culture, regardless of the type of mesh used. Results: Only in cultures containing monofilament mesh and stimulated with estriol the high rate of collagen type III synthesis persisted until the end of the experiment. Paradoxically, the highest total production of PIIINP was observed in culture treated with tamoxifen, both for multifilament and monofilament meshes. Conclusion: The rate of collagen type III synthesis by pubocervical fascia fibroblast cultured with polypropylene meshes is subjected to modulation by estrogens and antiestrogens.