BACKGROUND: The aging global population is increasing the attention to cognitive decline in older individuals. OBJECTIVE: This study sought to examine the potential link between the neutrophil percentage-to-albumin ratio (NPAR) and cognitive function. METHODS: We analyzed data from the National Health and Nutrition Examination Survey 2011-2014 using multivariate logistic regression and smooth curve fitting, to investigate the correlation between NPAR and cognitive performance. Restricted cubic spline analysis assessed the linear relationship with high-risk cognitive dysfunction, while piecewise linear regression identified thresholds. Subgroup analyses confirmed the consistency and reliability of our findings. RESULTS: Our study included data from 2759 individuals aged >60 years. NPAR showed a significant correlation with Consortium to Establish a Registry for Alzheimer's Disease (CERAD) word learning score, CERAD delayed recall score, total z-score and a high risk of cognitive dysfunction. Furthermore, there were statistically significant trends in the changes in CERAD word learning, digit symbol substitution test, and CERAD delayed recall scores as the NPAR quartile increased, these trends were inverted U-shaped. When the NPAR exceeded 14.57, there was a positive association with the likelihood of a high risk of cognitive impairment. The link between NPAR and cognitive performance was notably stronger in individuals with moderate body mass index and those aged 73-80 years. CONCLUSIONS: A strong link was observed between the NPAR and cognitive function. NPAR may serve as a tool to identify individuals at increased risk of cognitive decline.