This Expert Council focuses on the meta-analysis of studies on the risk of atrial fibrillation (AF) in patients taking omega-3 polyunsaturated fatty acids (PUFA) and of data on the omega-3 PUFA treatment in patients with cardiovascular and kidney diseases.The major statements of the Expert Council: the meta-analysis of AF risk in patients taking omega-3 PUFA showed an increased risk of this arrhythmia. However, it should be taken into account that the risk of complications was low, and there was no significant increase in the risk of AF when omega-3 PUFA was used at a dose of ≤1 g and a standard dose of the only omega-3 PUFA drug registered in the Russian Federation, considering all AF episodes in the ASCEND study.At the present time, according to Russian and international clinical guidelines, the use of omega-3 PUFA can be considered in the following cases: • for patients with chronic heart failure (CHF) with reduced left ventricular ejection fraction as a supplement to the basic therapy (2B class of recommendations according to the 2020 Russian Society of Cardiology guidelines (RSC) and the 2022 AHA / ACC / HFSA guidelines); • for patients with hypertriglyceridemia (>1.5 mmol/l) as a part of combination therapy (IIb class of recommendations and B level of evidence according to the 2021 European guidelines on cardiovascular disease prevention, etc.); • for adult patients with stage 3-4 chronic kidney disease (CKD), long-chain omega-3 PUFA 2 g/day is recommended for reducing the level of triglycerides (2C class of recommendations). Data on the use of omega-3 PUFA for other indications are heterogenous, which can be partially explained by using different form and doses of the drugs.