Skin flap ischemia has been associated with the presence of free radicals. In this study we designed a suture-induced delay model in 30 rats using two different suture techniques. A total of 13 rats that underwent McFarlane's acute random-flap model served as controls. We found a statistically significant difference between the flaps of the experimental and control groups regarding the viability of flaps. Malondialdehyde levels in tissue samples taken from the proximal and distal ends of each flap were estimated at 6 and 24 hours postoperatively. Malondialdehyde levels in the experimental groups were found to be quite lower than those of the controls. In conclusion, the suture-induced delay model seems to be effective in improving flap viability. Also, we found lower malondialdehyde levels in experimental groups compared with controls.