Background and Objectives: This study aimed to investigate the protective effect of polydeoxyribonucleotide (PDRN) against skin flap necrosis in a murine skin flap model.Materials and Method Twenty mice with rectangular skin flaps on the dorsum were randomly divided into the PDRN (n=10) and pentobarbital sodium (PBS) (n=10) injection groups. PDRN (8 mg/kg) was subdermally injected at 12 different points immediately after the operation. After 7 days, the flap perfusions were evaluated using a laser speckle contrast imaging (LSCI) system, and specimens were collected for immunohistochemistry analysis. Results: The percentage of survival area relative to the total flap area was significantly higher in the PDRN group (60.87%±7.63%) than in the PBS group (45.23%±10.72%) (p<0.05). The mean LSCI perfusion signal of the distal part of the skin flap in the PBS group was 0.57±0.12, and that in the PDRN group was 0.74±0.13 (p<0.05). The PDRN group had a significantly lower interleukin 1 beta expression than the PBS group and higher vascular endothelial growth factor α expression than the PBS group (p<0.05). Conclusion These findings suggest that subdermally injected PDRN is more effective in enhancing flap survival during necrosis.