This evidence report is one of several reports that address topics related to omega-3 fatty acid The aim of the reports is to summarize the current evidence on the health effects of omega-3 fatty acids (eicosapentaenoic acid EPA; chemical abbreviation: 20:5 n-3], docosahexaenoic acid DHA; 22:6 n-3], alpha-linolenic acid ALA, 18:3 n-3], and docosapentaenoic acid DPA, 22:5 n-3]) on the following: cardiovascular disease, cancer, child and maternal health, eye health, gastrointestinal diseases, kidney diseases, asthma, autoimmune diseases, immune-mediated diseases, organ transplantation, mental health, and neurological diseases and conditions. In addition to informing the research community and the public on the effects of omega-3 fatty acids on various health conditions, it is anticipated that the findings of the reports will also be used to help define the agenda for future research. Nine key questions are addressed in this report. Question 1. What is the evidence that omega-3 fatty acid supplementation reduced rejection episodes or graft failure in patients (adults or children) who received an organ transplant? Question 2. What is the evidence that omega-3 fatty acid supplementation is renoprotective (improves glomerular filtration rate or increases kidney size) or is protective against primary kidney disease recurrence following kidney transplantation? Question 3. What is the evidence that omega-3 fatty acid supplementation lowers cardiovascular disease risk factors or events in organ transplant recipients (adults or children)? Question 4. What is the evidence that omega-3 fatty acid supplementation reduces serious infectious complications following organ transplantation? Question 5. What is the evidence that any benefits to organ transplant recipients from omega-3 fatty acid supplementation differ in different subsets of patients? Question 6. What is the evidence that effects of omega-3 fatty acid supplementation on outcomes of interest vary depending on the time of administration relative to transplantation procedures (pre- or post-transplant)? Question 7. What is the evidence in patients (adults or children) who receive an organ transplant that the benefits of omega-3 fatty acid supplementation interact with the concomitant administration of various immunosuppressive agents/drugs? Question 8. What is the evidence in patients (adults or children) who receive an organ transplant that serum levels of immunosuppressive agents/drugs are altered by omega-3 fatty acid supplementation? Question 9. What is the evidence in patients (adults or children) who receive an organ transplant that omega-3 fatty acid supplementation can replace or reduce the need for other more potent anti-inflammatory or immunosuppressive drugs (such as steroids and non-steroidal anti-inflammatory drugs)?