Platelets are a natural source of growth factors and cytokines that promote wound healing, and platelet-rich fibrin contains concentrated growth factors. Growth factors in platelet-rich fibrin may promote wound repair. In this study the effect of platelet-rich fibrin was evaluated in a dog model of cutaneous incisional wounds using histology and semi-quantitative evaluation. A pair of ten-centimeter full-thickness parallel linear cutaneous wounds were created on the backs of 15 dogs on the both sides of vertebral column. On the left side the platelet-rich fibrin clot was applied to the edges of the wound (Treatment group) and the right side received nothing (Control group). All wounds were then closed with 3-0 non-absorbable Nylon suture. The dogs were divided into three groups of five dogs. The wound tissues were sampled by electrosurgery in group one after 3 days, group two after 7 days and group three after 14 days post surgery. For each specimen, histopathological examination and semi-quantitative evaluation was performed by light microscopy using Hematoxylin & Eosin and Masson’s trichrome staining. The results demonstrated that platelet-rich fibrin improved and accelerated cutaneous incisional wound healing.