Objective To investigate the relationship between serum levels of homocysteine (HCy) and adiponectin (APN) in patients with type 2 diabetes mellitus(T2DM).Methods 65 patients with T2DM (diabetes mellitus group) and 25 healthy controls (control group) matched in the age and sex were recruited in the study.Serum HCy,APN,fasting plasma glucose (FPG),fasting insulin (FINS),total cholesterol (TC) and triglyceride (TG) were simultaneously measured.The homeostatic model assessment for insulin resistance(HOMA-IR) was calculated according to FPG and FINS.All the serum indicators were compared between the two groups.Results Serum level of HCy in T2DM group was (15.74 ± 2.76) μmol/L,which was significantly higher than (6.98 ± 1.94) μmol/L in the healthy control group (t =16.88,P ＜ 0.01).The serum level of APN in T2DM group was (8.14 ± 2.70) mg/L,which was significantly lower than (16.10 ± 1.93)mg/L in the healthy control group (t =13.44,P ＜ 0.01).Serum levels of FPG,HOMA-IR,TC,TG in T2DM group were significantly higher than those in the healthy control group (t =10.62,17.49,6.30,7.52,P ＜ 0.05).Serum level of APN in HCy ≥ 15μmol/L group was significantly decreased compared with HCy ＜ 15μmol/L group.Serum level of HCy was negatively correlated with APN in T2DM group after the influence of FPG,HOMA-IR,TG,TC were corrected in the partial correlation analysis.Conclusion In T2DM group,serum level of HCy was increased,but serum level of APN was decreased,serum HCy was negatively correlated with APN,higher serum level of HCy and lower serum level of APN are related with the process of insulin resistance and T2DM.