ABSTRACTBackground: Recommendations for therapy insulin resistance are metformin and thiazolidindion. Sideeffects of thiazolidindion due to peripheral edema occurs to 2-5% and increased 5-15% when combinedwith insulin therapy. Telmisartan, an angiotensin receptor blocker, has anti-hypertensive effects and improveinsulin resistance. Telmisartan effect on peroxisome proliferator activated receptor γ agonist and has the samestructure of the group thiazolidindion, pioglitazone. The research objective was to determine the effectsof telmisartan and metformin on insulin resistance in metabolic syndrome patients with insulin therapy.Methods: This study used a before-after design. The study was conducted in the internal medicine clinic of theendocrinology department of Dr. Sardjito Hospital Yogyakarta. Subjects were patients who met the diagnosis of metabolic syndrome based on the IDF 2005, hypertension and received insulin therapy. Subjects given metforminand telmisartan therapy for 12 weeks. Subjects examined HOMA IR before and after treatment. The averagedecrease in HOMA IR was tested by paired t-test or Wilcoxon test. P value <0.05 was considered signifi cant.Result: The total sample were 27 subjects. Data analysis was performed on 11 subjects. Fasting bloodglucose before and after treatment was signifi cantly decreased (p<0.001) whereas the fasting insulin levelsincreased. HOMA IR was signifi cantly decreased after treatment {p = 0.004 (5.79 â 20.26), CI 95%}.Conclusion: this study found insulin resistance decreased signifi cantly in patients with the metabolicsyndrome of insulin therapy who received metformin and telmisartan.Keywords : metabolic syndrome, insulin therapy, metformin, telmisartan, HOMA IR