Background: Most animal studies have shown that trans-10 and cis-12 isomers of Conjugated linoleic Acid, (CLA) tend to increase insulin resistance. But the effect of equal isomers of CLA (50: 50 ratios of cis-9, trans-11: trans-10, cis-12 isomers) on lipid profiles, glucose, and insulin resistance and sensitivity in postmenopausal women is not clear.Methods: In the present study, we performed a randomized, double blind, placebo-controlled trial to examine the changes in lipid profiles, glucose, and insulin concentration following 4 CLAG80 capsules containing 3.2g CLA (50: 50 ratios of cis-9, trans-11: trans-10, cis-12 isomers) or 4 placebo capsules supplementation for 12 weeks in post-menopausal women. Seventy six healthy post-menopausal women were randomized to receive placebo or 3.2 g CLA for 12 weeks. Anthropometric measurements were done. Blood samples were collected after 12-14 hours fasting before and after intervention. Insulin resistance and insulin sensitivity were estimated based on the homeostasis (HOMA) and QUIKI models. In weeks 0, 6 and 12 during the trial, subjects completed 3d dietary records. These dietary records were coded by the same dietitian, and analyzed with the Food Processor program. Result: There were no significant effect on serum lipids, insulin, glucose, insulin resistance and insulin sensitivity over 12 weeks in postmenopausal women.Conclusion: Mixed isomer CLA supplementation had no effect on serum insulin, lipids profile, glucose and insulin resistance/sensitivity during 12 weeks of intervention in postmenopausal women.