The aim of this study was to investigate quantitative mRNA expression of matrix metalloproteinases MMP-1, MMP-2, MMP-9, and their inhibitors, the tissue inhibitors of metalloproteinases TIMP-1, TIMP-2 and TIMP-3, in vaginal wall tissue from women with stress urinary incontinence compared to continent controls. Vaginal wall tissues were obtained from 7 women with stress urinary incontinence/severe pelvic prolapse and 15 continent controls. RNA was then extracted and quantified. Quantitative competitive reverse transcription (QC-RT-PCR) was carried out with oligonucleotide primers to quantify MMP-1, MMP-2, MMP-9, TIMP-1, TIMP-2 and TIMP-3 mRNA expression. Stress continent women demonstrated a significant decrease in TIMP-1 and mRNA expression (P= 0.03). There was no difference in TIMP-2, TIMP-3, MMP-2 or MMP-9 mRNA expression between stress incontinent women and controls. However, MMP-1 mRNA expression was significantly increased (P= 0.05) in the incontinent group and the MMP-1/TIMP-1 ratio (P= 0.04) was consistent with increased collagen degradation in the stress incontinence. Stress incontinent women demonstrated an increase in MMP-1 mRNA expression and a decrease in the inhibitor TIMP-1 mRNA expression. Both these findings are consistent with increased collagen breakdown as a pathologic etiology of incontinence.