Summary The past few decades have been a period of rapid expansion of knowledge of omega-3 polyunsaturated fatty acids (PUFAs). It is well known that the central nervous system is highly enriched in long-chain PUFA of the omega-6 and omega-3 series. These fatty acids are structural components of neuronal membranes and influence the cellular function both directly, through effects on membrane properties, and also by acting as a precursor pool for lipid-derived messengers. This review focuses on the results of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation in population with Alzheimer’s disease (AD). We screened 83 titles, reviewed 50 studies and found 5 studies that pertained to our objectives. Patients with AD have been shown to be deficient in DHA, and supplementing them with EPA+DHA reverses this deficiency. However, the screened double-blind, placebo-controlled clinical trials confirmed the benefits of supplementation with omega-3 PUFAs only for patients with very mild cognitive impairment.