This observational study focuses on the effects of marine n-3 polyunsaturated fatty acids (PUFAs) intake, measured as fatty acid levels in plasma phospholipids, and mortality and graft loss endpoints in renal transplant recipients. Data on morbidity, mortality and graft loss in The Norwegian Renal Registry is matched against data on fatty acid composition in a large renal transplantation cohort of approximately 2000 patients with a median follow up time of about 5 years. It is a follow up study, although retrospectively evaluated. It will evaluate the role of marine n-3 PUFAs as a prognostic marker in renal transplantation by investigating the association between the levels (weight percentage of total fatty acids) of marine n-3 PUFAs in plasma phospholipids and events, including mortality and graft loss.