Malnutrition is one of the stronger predictors of morbi-mortality in end-stage kidney disease patients. Moreover, malnutrition in hospitalized patients severely affects multiple clinical outcomes, increasing the risk of complications. The Nutritional Risk Index and Geriatric Nutritional Risk Index are indexes used to evaluate the risk of malnutrition in hospitalized adults, which have been validated for dialysis patients and have been reported to be a validated prognostic index of nutrition-related morbidity and mortality. : The aim of this study is to evaluate the prevalence of early postoperative infections and their possible relationship with malnutrition in renal transplantation. : We conducted a retrospective observational study, including all patients who received a kidney transplant, a total of 140, between January 2020 and December 2023, at a tertiary-level Spanish hospital. : The average GNRI was 110.1 ± 11.6, equivalent to adequate nutrition, and only 16.4% of patients were at risk of malnutrition. The mean NRI was 111.4 ± 11.8, equivalent to no risk of malnutrition, and only 17.2% of patients had a moderate-to-severe risk of malnutrition. A total of 30 patients (21.4%) required oral nutritional supplementation at discharge, especially modular protein supplements (86.7%), and 52 patients (37.1%) presented an infection during their stay. The most frequent infections were urinary tract infections (69.8% of the total). Malnutrition calculated by the GNRI or NRI correlated to a longer postoperative hospital stay and a higher rate of infectious complications ( < 0.05). : Malnourished patients have a higher risk of early postoperative complications, including infection, and a longer hospitalization stay. The evaluation of nutritional status for the diagnosis and treatment of malnutrition is strongly recommended in ESKD patients on the waiting list for a kidney transplant.