Background <p>Elderly inpatients are at high risk for hospital-acquired pneumonia (HAP). The association between dietary carotene and HAP remains unclear.</p> Methods <p>This cross-sectional study included 165 patients aged ≥ 80 years. Dietary carotene intake was assessed via 72-hour recall and food weighing, analyzed using the China Food Composition Table. Based on tertiles of dietary carotene intake, patients were stratified into low- (T1, &lt; 713.3&#xa0;µg/day; <i>n</i> = 55), medium- (T2, 713.4–2101.4&#xa0;µg/day; <i>n</i> = 54), and high-intake groups (T3, ≥ 2101.6&#xa0;µg/day; <i>n</i> = 56). Multivariable logistic regression, restricted cubic splines, threshold analysis and subgroup analyses were used to evaluate the relationship between dietary carotene intake and HAP.</p> Results <p>A total of 165 hospitalized senior patients aged 80 years or older were included, with an average age of 89.7 ± 9.8 years. Of these, 30.9% (51/165) had HAP. After adjusting for confounding factors (age, BMI, co-morbidities, energy intake, etc.), the risk of pneumonia in the moderate dietary carotene intake group (T2) was 80% lower than that in the lowest dietary carotene intake group (T1) (OR = 0.20, 95% CI: 0.06–0.71). Restricted cubic spline analysis revealed a nonlinear association between carotene intake and HAP risk (<i>P</i> for nonlinearity = 0.003). The inflection point analysis indicated a significant reduction in pneumonia risk with increasing carotene intake below 1273.7&#xa0;µg/d. Beyond this threshold, however, the dose-response curve plateaued, suggesting no additional benefit from higher intake. Subgroup analyses (by diabetes, CKD, nutrition risk) showed consistent results.</p> Conclusions <p>Increased dietary carotenoids intake was inversely associated with the prevalence of HAP, demonstrating a dose-response relationship below a threshold of 1273.7&#xa0;µg/d.</p>