Despite improvements in ventral hernia repair techniques, their recurrence rates are unacceptably high. Increased levels of matrix metalloproteinases (MMPs) and reduced collagen-1 to -3 ratios are implicated in incisional hernia formation. We have recently shown doxycycline treatment for 4 wk after hernia repair reduced MMP levels, significantly increased collagen-1 to -3 ratios, and increased tensile strength of repaired interface fascia. However, this increase was not statistically significant. In this study, we extended treatment duration to determine whether this would impact the tensile strength of the repaired interface fascia. Thirty-two male Sprague-Dawley rats underwent incision hernia creation and subsequent repair with polypropylene mesh. The animals received either saline (n = 16) or doxycycline (n = 16) beginning from 1 day before hernia repair until the end of survival time of 6 wk (n = 16) or 12 wk (n = 16). Tissue samples were investigated for MMPs and collagen subtypes using Western blot procedures, and tensiometric analysis was performed. At both 6 and 12 wk after hernia repair, the tensiometric strength of doxycycline-treated mesh to fascia interface (MFI) tissue showed a statistically significant increase when compared with untreated control MFI. In both groups, collagen-1, -2, and -3 ratios were remarkably increased in doxycycline-treated MFI. At 6 wk, the doxycycline-treated MFI group showed a significant decrease in MMP-2, an increase in MMP-3, and no change in MMP-9. At 12 wk, MMP-9 showed a remarkable reduction, whereas MMP-2 and -3 protein levels increased in the doxycycline-treated MFI group. Doxycycline administration results in significantly improved strength of repaired fascial interface tissue along with a remarkable increase in collagen-1, -2, and -3 ratios.