OBJECTIVES: Exenatide is a new antidiabetic agent which is an analog of incretin (glucagon-like peptide 1) with a adjunctive therapy with type 2 diabetes mellitus (T2DM),and has adverse events of nausea, vomiting and poor appetite. To assess the clinical efficacy of exenatide in T2DM. METHODS: Inclusion criteria were T2DM with inadequate glycemic control under oral antidiabetic agnets or insulin therapy. Exenatide were added on by the reatment course of exenatide is 5μg twice a day at first month and then adjusted to 10μg twice a day if tolerated. The primary outcomes are influence on HbA1C level and body weight RESULTS: Eighteen patients, who were 7 male and 11 female with mean age of 43.46, were recruited. Of them had a mean body weight of 97.15kg and mean HbA1C of 9.1%. HbA1c improved significantly after 3 months and 6 months with mean reduction of  0.75%(p<0.002) and 0.97%(p<0.009). Mean body weight mild decreased at 3 months (4.33 kg) and reduced significantly at 4 months and 6 months with 5kg (p<0.005) and 9.74kg (p<0.0006). CONCLUSIONS: Exenatide improve HbA1c and body weight greatly within 6 months in a local hospital and may have great affect on the changing of life style, like diet control and frequency of  Self-Monitoring of Blood Glucose. In future, a larger and long time study would need to demonstrate the validity of exenatide on the taiwanese.