BackgroundThe effect of prognostic nutritional index (PNI) on predicting prognosis of endometrial cancer (EC) patients has been widely analyzed, but no consistent findings are obtained. We therefore performed a meta-analysis for determining accurate role of PNI in predicting EC prognosis. MethodsWe comprehensively searched PubMed, Web of Science, Embase, Cochrane Library, and CNKI databases from inception till January 5, 2024. Correlation between PNI and survival outcomes in EC was evaluated by pooled hazard ratios (HRs) and 95 % confidence intervals (CIs). ResultsThere were altogether eight articles involving 3,164 patients enrolled into this meta-analysis. According to our pooled results, low PNI significantly predicted the dismal overall survival (OS) (HR = 1.72, 95%CI = 1.33–2.22, p < 0.001) and inferior progression-free survival (PFS)/disease-free survival (DFS)/recurrence-free survival (RFS) (HR = 2.49, 95%CI = 1.62–3.84, p < 0.001) for EC patients. Furthermore, as revealed by our pooled results, a decreased PNI was significantly connected to FIGO stage III-IV (OR = 2.06, 95%CI = 1.42–2.99, p < 0.001), tumor grade of G3 (OR = 1.68, 95%CI = 1.32–2.14, p < 0.001), presence of lymphovascular space invasion (LVSI) (OR = 1.72, 95%CI = 1.14–2.61, p = 0.010), and presence of myometrial invasion (MMI) (OR = 2.04, 95%CI = 1.51–2.77, p < 0.001) in EC. ConclusionAccording to our meta-analysis results, the decreased PNI is markedly related to poor OS and inferior PFS/DFS/RFS of EC patients. Additionally, decreased PNI was indicative of features implying tumor progression and development in EC.