Abstract: Objective　To investigate the relationship between the fasting levels and levels after diet for 2h of free fatty acid (FFA) and insulin resistance in patients with type 2 diabetes mellitus (T2DM).  Methods　　A total of 100 T2DM patients were enrolled and classified into good-control group and no-good-control group according to Asian Diabetes Forum, and 50 healthy controls were also enrolled. Their glycosylated hemoglobin (HbA1c)，fast insulin (FINS), fast plasma glucose (FPG), 2 h plasma glucose (2 h PG), fast FFA and 2 h FFA were determined. Homeostasis model assessment-insulin resistance index (HOMA-IR) was evaluated by HOMA.  Results　Compared with those in control group, FPG, 2 h PG, FFA, 2 h FFA, HbA1c and HOMA-IR increased significantly in T2DM group (P＜0.01). The parameters in no-good-control group were higher than those in good-control group (P＜0.05). FFA and 2 h FFA were positively correlated with HOMA-IR, HbA1c, FPG and 2 h PG（r=0.910 and 0.876, 0.851 and 0.759, 0.908 and 0.746 and 0.769 and 0.674，P＜0.01）.  Conclusions　The increasing of FFA levels is positively related with insulin resistance in T2DM patients, and may play an important role in the development of T2DM.

Key words: Free fatty acid, Insulin resistance, Type 2 diabetes mellitus