Purpose <p>The Prognostic Nutritional Index (PNI), calculated using serum albumin levels and blood lymphocyte count, reflects a patient’s nutritional and immune status. It is commonly used as a prognostic tool following oncological surgery and in certain cardiovascular conditions. This study aims to assess whether the PNI can also serve as a prognostic indicator in patients undergoing surgical aortic valve replacement (SAVR).</p> Methods <p>A total of 471 low-risk patients with EuroSCORE II (European System for Cardiac Operative Risk Evaluation&#xa0;II) of ≤4%, who underwent isolated SAVR, were retrospectively analysed. Patients were divided into two groups&#xa0;based on their PNI values (cut-off, 46.75). Outcomes such as length of hospital stay, 30-day mortality, 1-year&#xa0;survival, and rehospitalization rates were compared between the groups.</p> Results <p>The Low PNI group consisted of 116 patients, while the High PNI group included 355 patients. The latter were younger, but both groups had comparable comorbidities. All patients underwent SAVR with a bioprosthesis. There was no significant difference in 30-day mortality between the groups (Low PNI, 2.6% vs. High PNI, 0.9%, <i>p</i> = 0.162). However, the 1-year survival rate was significantly lower in the Low PNI group (Low PNI, 5.2 ± 4.1% vs. High PNI, 1.7 ± 1.3%, <i>p</i> = 0.039). Additionally, the 1-year rehospitalization rate was significantly higher in the Low PNI group (Low PNI, 13.8 ± 6.3% vs. High PNI, 7.7 ± 2.7%, <i>p</i> = 0.040). Multivariate analysis identified PNI as a protective factor, while mechanical ventilation was associated with increased risk of death or rehospitalization at 1-year after SAVR.</p> Conclusions <p>The PNI is an inexpensive, accessible, and reliable tool that can be easily integrated into existing risk stratification scores for SAVR.</p> Graphical Abstract <p></p>