Despite the fast development of technology in the world, diabetic foot wounds cause deaths and massive economical losses. Diabetes comes first among the reasons of non traumatic foot amputations. To reduce the healing time of these fast progressing wounds, effective wound dressings are in high demand. In our study, sheep small intestinal submucosa (SIS) based biocompatible sponges were prepared after SIS decellularization and their wound healing potential was investigated on full thickness skin defects in a diabetic rat model. The decellularized SIS membranes had no cytotoxic effects on human fibroblasts and supported capillary formation by HUVECs in a fibroblast-HUVEC co-culture. Glutaraldehyde crosslinked sponges of three different compositions were prepared to test in a diabetic rat model: gelatin (GS), gelatin: hyaluronic acid (GS:HA) and gelatin: hyaluronic acid: SIS (GS:HA:SIS). The GS:HA:SIS sponges underwent a 24.8 +/- 5.4% weight loss in a 7-dayin vitroerosion test. All sponges had a similar Young's modulus under compression but GS:HA:SIS had the highest (5.00 +/- 0.04 kPa). Statistical analyses of histopathological results of a 12-dayin vivoexperiment revealed no significant difference among the control, GS, GS:HA, and GS:HA:SIS transplanted groups in terms of granulation tissue thickness, collagen deposition, capillary vessel formation, and foreign body reaction (P > 0.05). On the other hand, in the GS:HA:SIS transplanted group 80% of the animals had a complete epidermal regeneration and this was significantly different than the control group (30%, P < 0.05). Preclinical studies revealed that the ECM of sheep small intestinal submucosa can be used as an effective biomaterial in diabetic wound healing.