Background and aimsThe relationship between uric acid to high-density lipoprotein cholesterol ratio (UHR) and mortality in individuals with diabetes remains uncertain. This study aimed to explore the relationship between serum UHR and all-cause and cardiovascular disease (CVD) mortality in adults with diabetes. Methods and resultsA total of 5665 patients with diabetes were enrolled from the 2005–2018 National Health and Nutrition Examination Survey (NHANES). Mortality data were determined through the National Death Index (NDI) until December 31, 2019. The multivariate hazard ratio (HR) and 95% confidence interval (CI) were examined by Cox proportional risk modeling and threshold effects analysis. Stratified analyses were conducted to identify the populations with high-risk mortality. Among the participants with diabetes, 1088 all-cause mortality, containing 310 CVD mortality occurred. Following adjustment for multivariate, higher UHR was significantly and nonlinearly associated with increased all-cause mortality (HR 1.02, 95% CI 1.02–1.02) and CVD mortality (HR 1.03, 95% CI 1.03–1.03). Furthermore, a U-shaped relationship between UHR and all-cause and CVD mortality, with a plateau at 12.57% for all-cause mortality and 9.86% for CVD mortality. Below the inflection points, a higher UHR was associated with a 4% reduced risk for all-cause mortality. Conversely, exceeding the inflection points, a 4% higher risk for all-cause and a 3% higher risk for CVD mortality associated with elevated UHR. ConclusionsNonlinearity of UHR with all-cause and CVD mortality was observed in adults with diabetes in the United States, with thresholds identified at 12.57% for all-cause and 9.86% for CVD mortality respectively.