Objectives: Malnutrition is common in patients undergoing hemodialysis and is a powerful predictor of morbidity and mortality. This study aimed to investigate the impact of nutritional status on permanent catheter patency in elderly patients over 75 years of age undergoing dialysis with tunneled dialysis catheters. Methods: We retrospectively reviewed the records of 383 patients whose nutritional factors and BCM was measured at the same time as starting dialysis in the period between January 14, 2020 and September 31, 2023 at Chungnam National University Hospital. The relationships between permanent catheter patency at 180 days and BCM parameters, laboratory tests, age, sex, comorbidities, and medications at baseline were studied using Kaplan–Meier survival curves and multivariate cox proportional hazards analysis. Results: Non-patency of dialysis catheter occurred at a higher rate in women (69.8%) than in men (30.2%). Age and sexual difference showed significant results of p value <0.05, and CRP and albumin in pre-dialysis blood tests were significant results of p value <0.05. Most of BCM parameters and BCM did not show significant results of p value <0.05 except ICW. There were more patients with VA creation in the patent group (86.4%) than in the non-patent group (50.8%), showing a statistically significant result of p value <0.05. Permanent catheter patency was observed to be superior at low CONUT score (p < 0.05). After adjustment for covariates, the CONUT score remained an independent factor associated with permanent catheter patency survival. Conclusions: Nutritional scores measured before the start of dialysis are expected to play an important role in predicting the prognosis for permanent catheter patency survival. Identifying and managing a group of patients with very poor nutrient scores is expected to be of great help in improving the treatment and prognosis of maintenance hemodialysis patients in the future.