Klotho is a protein with various biological functions, including anti-aging effects. Although research suggests Klotho plays a key role in auditory function, the relationship between serum Klotho levels and high-frequency hearing loss (HFHL) in older adults remains unclear. We analyzed data from individuals aged 70-79 years participating in the 2009-2010 cycle of the National Health and Nutrition Examination Survey. Multivariate logistic regression models were employed to assess the relationship between serum Klotho levels and HFHL. Restricted cubic splines were utilized to evaluate linearity and examine the dose-response relationship. Additionally, we performed subgroup analyses to evaluate the consistency of this relationship across various subgroups. In this study of 422 elderly individuals aged 70-79 years (mean age 73.8 years, with 47.4% male participants), the median serum Klotho concentration was 754.6 pg/mL. Multivariable logistic regression analysis consistently demonstrated that higher serum Klotho levels were associated with a reduced risk of HFHL across various models (ORs: 0.24-0.32, p = 0.020-0.028). Additionally, restricted cubic spline analysis confirmed a linear negative association between serum Klotho levels and HFHL risk, with a p-value for nonlinearity of 0.474. Subgroup analyses did not reveal any statistically significant interactions modifying this relationship. Serum Klotho levels are inversely associated with the risk of HFHL. 3 Laryngoscope, 2024 Laryngoscope, 2024.