ABSTRACT INTRODUCTION Diabetic foot ulcers are a chronic complication in patients with diabetes mellitus. They appear as a result of the combination of diabetic polyneuropathy and angiopathy, and in many cases require amputation of the affected extremity. Clinical trials have demonstrated that repeated local infiltration with Heberprot-P can improve healing of chronic diabetic foot ulcers. Although there is evidence of its effects as a granulation stimulator and on cell migration and proliferation, genetic control mechanisms explaining its anti-inflammatory and oxidative stress reduction properties are not yet thoroughly understood. OBJECTIVE Analyze changes in expression of genes involved in healing after treatment of diabetic foot ulcers with Heberprot-P. METHODS Biopsies were collected from diabetic foot ulcers of 10 responding patients before and after 2 weeks’ treatment with Heberprot-P (75-μg applied intralesionally 3 times per week). Total RNA was obtained and quantitative PCR used to determine expression of 26 genes related to inflammation, oxidative stress, cell proliferation, angiogenesis and extracellular matrix formation. Genetic expression was quantified before and after treatment using REST 2009 v2.0.13. RESULTS After treatment, there was a statistically significant increase in expression of genes related to cell proliferation, angiogenesis and formation of extracellular matrix (PDGFB, CDK4, P21, TP53, ANGPT1, COL1A1, MMP2 and TIMP2). A significant decrease was observed in gene expression related to inflammatory processes and oxidative stress (NFKB1, TNFA and IL-1A). CONCLUSIONS Our findings suggest that Heberprot-P’s healing action on diabetic foot ulcers is mediated through changes in genetic expression that reduce hypoxia, inflammation and oxidative stress, and at the same time increase cell proliferation, collagen synthesis and extracellular matrix remodeling. The kinetics of expression of two genes related to extracellular matrix formation needs further exploration.