The objective of this study is to assess the predictive significance of lactate dehydrogenase-to-albumin ratio (LAR) in patients with upper tract urothelial carcinoma (UTUC) who have undergone radical nephroureterectomy (RNU).We performed a retrospective analysis on patients with UTUC at West China Hospital, covering the period from May 2003 to June 2019. The optimal cut point of LAR was determined using the X-Tile program. Relevant statistical methods included the utilization of Kaplan-Meier curves for survival estimation and the application of Cox proportional hazard model for risk evaluation. A nomogram was constructed to predict the 3-year and 5-year CSS and the predictive performance was also evaluated.A cohort of 577 patients with UTUC who underwent RNU were included in the study, and the threshold value of LAR was 5.07. LAR ≥ 5.07 was associated with worse CSS [hazard ratio (HR) = 1.72; 95% confidence interval (95%CI): 1.18-2.50; P = 0.005] in fully adjusted Cox regression analysis. In addition, the nomogram utilizing the LAR exhibited excellent prognostic performance in predicting CSS, with time-dependent areas under the curve (tAUC) values of 0.814 and 0.781 for 3-year and 5-year CSS, respectively.Preoperative LAR could be regarded as a valuable individualized tool for clinical decision-making, as it independently predicts CSS in UTUC patients undergoing RNU.© 2025. The Author(s).