Nutritional status is a novel approach to prognostic assessment in patients with cardiovascular disease. However, assessment of nutritional status in elderly patients is challenging due to the significant differences between young patients. The TCBI (Triglycerides × Total cholesterol × Body Weight Index) is a novel and simple nutritional index for predicting long-term outcomes in patients with coronary artery disease. This retrospective study evaluated the efficacy of TCBI in 597 elderly (≥ 75 years) patients enrolled in the SHINANO 5 year registry. The SHINANO 5 year registry, a prospective observational multicenter cohort study, had enrolled 1501 consecutive patients who underwent elective/urgent percutaneous coronary intervention (PCI). In this study, patients were categorized into TCBI quartile groups. The primary endpoints were the occurrence of major adverse cardiac and cerebrovascular events (MACCE), including all-cause death, stroke, and myocardial infarction at 5 year. The mean duration of follow up was 4.3 ± 1.7 years. The average patient age was 80.9 ± 4.3 years. MACCE was observed in 61 (40.9%) patients in the lowest TCBI quartile group. Kaplan-Meier analysis demonstrated an inverse relationship between MACCE and TCBI (log-lank P < 0.001). Multivariate analysis demonstrated that low TCBI significantly predicted the incidence of MACCE (hazard ratio: 1.44, 95% confidence interval: 1.03-2.00; P = 0.031). The TCBI is useful in predicting long-term outcomes in elderly patients undergoing PCI.