BACKGROUND & AIMS: Cardiovascular disease (CVD) is a significant cause of mortality and rising healthcare costs, involving numerous chronic and nutritional risk. Although several studies have reported that malnutrition based on the Global Leadership Initiative on Malnutrition (GLIM) criteria is associated with mortality in patients with CVD, they have not evaluated this association in terms of malnutrition severity (moderate or severe). Furthermore, the relationship between malnutrition combined with renal dysfunction, a risk factor for death in CVD patients, and mortality has not been previously evaluated. Thus, we aimed to assess the association between malnutrition severity and mortality, as well as malnutrition status stratified by kidney function and mortality, in patients hospitalized due to CVD events. METHODS: This single-centre, retrospective cohort study included 621 patients with CVD aged ≥18 years admitted to Aichi Medical University between 2019 and 2020. The relationship between nutritional status based on the GLIM criteria (without malnutrition, moderate malnutrition, or severe malnutrition) and the incidence of all-cause mortality was evaluated by multivariable Cox proportional hazards models. RESULTS: Patients with moderate and severe malnutrition were significantly more prone to mortality than those without malnutrition (adjusted hazard ratio [HR] of patients without, with moderate, and with severe malnutrition: 1.00 [reference], 1.94 [1.12-3.35], and 2.63 [1.53-4.50], respectively). Furthermore, we found the highest all-cause mortality rate in patients with malnutrition and a lower estimated glomerular filtration rate (eGFR <30 mL/min/1.73 m2) (adjusted HR, 10.1; confidence interval, 3.90-26.4) than in patients without malnutrition and normal eGFR (eGFR ≥60 mL/min/1.73 m2). CONCLUSIONS: The present study indicated that malnutrition according to the GLIM criteria was associated with increased all-cause mortality in patients with CVD, and malnutrition associated with kidney dysfunction was associated with a higher risk of mortality. These findings provide clinically relevant information to identify high mortality risk in patients with CVD and highlight the need for giving careful attention to malnutrition with kidney dysfunction among patients with CVD.