Phytosterols have cholesterol lowering properties by the inhibition of cholesterol absorption resulting from the higher affinity of plant sterols than of cholesterol for micelles. The purpose of this study was to evaluate the effects of micellar phytosterols on cholesterol absorption in humans. Twenty-four healthy adults (mean age: 37 yrs, 16 women and 8 men) underwent 4 cholesterol-absorption tests to compare the effects of micellar phytosterols supplement containing 500 mg, 300 mg, 200 mg phytosterols and placebo on cholesterol absorption in a cross-over design. Individual absorption tests were separated by 2 weeks. Using the single oral isotope method, inhibition of cholesterol absorption was determined by gas-chromatography mass spectrometry (GC-MS) measurement of the differences in plasma hexadeuterated cholesterol enrichment four days after test meals with or without phytosterols. Each test meal provided 500 kcal and 89.35 mg cholesterol including 40 mg tracer cholesterol. We used Mixed Model to test the significance of treatment effect with SAS software. All subjects were healthy, with mean LDL cholesterol values 99.5 짹 20.2 mg/dL and mean triglyceride 101.13 짹 50.1 mg/dL. Micellar phytosterols had significant overall effect on cholesterol absorption (p = 0.0002), reduced cholesterol absorption by 23.3 % at a dose of 300 mg phytosterols (p= 0.0004) and by 32.0% at a dose of 500 mg phytosterols (p= 0.0001) compared with the placebo. In conclusion, water-dispersible, micellar phytosterols reduced cholesterol absorption effectively at low doses than other preparation previously used.