Introduction: In this study the effects of low power helium-neon laser radiation on the cell population of open skin full thickness wound of rats were investigated from histological and biomechanical point of views. Materials and Methods: 90 Male rats were randomly divided into control and two experimental groups. Under general anesthesia and sterile conditions around open full thickness skin wound were made on the dorsum of each rat from day 1 intra-muscular injecting of 1/2 dose of anesthesizing drugs were given to all rats everyday: the rats of first experimental group (ex.1) received daily 51mj/cm2 low power helium-neon laser and the second experimental group (ex.2) received daily 20mj/cm2 of the same laser radiation. After 7 and 15 days of the treatments, rats were killed by ether and 2 samples from the wound bed and adjacent normal skin were obtained from them for histological and biomechanical studies. Samples of the histological study were prepared for rountine hitological study and stained by Hematoxylin and Eosin, and alcoholic solution of toluidine blue 1%. Fibroblasts, macrophges, neutrophils, endothelium of vessles, the number of vessels, mast cells were counted. The samples of biomechanical study were tested by tensiiometrical method and the tensile strength of each sample was obtained. Data were analysed by Krsukal Wallis method. Results: At day 7, there is a significant increase in the number of fibroblasts of experimental groups as compared with the control. Conclusion: Daily radiation of low power helium-neon laser with 5mj/cm2 and 20mj/cm2 energy density of an open skin full thickness wound of rats, accelerated significatly the proliferative phase of wound healing process.