Abstract： Objective To investigate the relationship between heme oxygenase and carbon monoxide(HO-CO) system and diabetic foot pathogenesis. Methods 30 diabetic foot (DF) patients , 25 diabetic patients without diabetic foot(DM), and 25 normal subjects (NC) were chosen. Serum CO level and expressions of HO-1 and HO-2 assayed by immunocytochemistry were measured. Results (1)The course was longer,the levels of fasting blood glucose and glycosylated hemoglobin were higher and serum CO and triglyceride were lower in DF group than in DM group. The blood pressure, total cholesterol and body mass index showed no difference between DF and DM groups. (2)The expressions of HO-1 and HO-2 were much weaker in DF group than in DM group. (3)There was negative correlation between serum CO and FBG(P=0.003). Conclusion The reduced expression of HO-CO system in diabetic patients may contribute to the occurrence and development of diabetic foot. Hyperglycaemia may be the main metabolic factor to influence the HO-CO system.