Objective: To systematically review the effect of dietary isoflavones or soy protein on the blood lipid levels, namely total cholesterol (TC), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C) and triglycerides (TG) in healthy postmenopausal women. Methods: A literature search was conducted through PubMed and MEDLINE database to locate studies in English on randomized controlled trials with isoflavones or soy diet interventions on healthy postmenopausal women. Quality assessment criteria were based on the CONSORT statement. Result: 15 studies with a total of 2008 healthy female participants were included in this systematic review. Interventions of soy diets and isoflavones resulted in inconsistent effects on blood lipid levels in postmenopausal women. Only 6 studies showed significant changes in lowering levels of TC, LDL-C or TG, or increasing levels of HDL-C. Conclusion: Overall, the clinical benefits of isoflavones and soy diets alone on blood lipid levels are inconclusive. Further systematic reviews and meta-analyses of randomized controlled trials are needed to evaluate whether isoflavones or soy diet are effective for the prevention of cardiovascular disease among postmenopausal women. ; published_or_final_version ; Public Health ; Master ; Master of Public Health