To assess the diagnostic performance and inter-observer agreement of a PREoperative sarcoma scoring based on ultrasound (PRESS-US) in differentiating uterine leiomyosarcoma (uLMS) from leiomyoma (LM).We conducted a retrospective evaluation of patients who underwent surgery and received standardized ultrasound examinations due to the presence of uterine myoma-like masses. Histological diagnosis was used as the reference standard. The masses were analyzed using morphological uterus sonographic assessment criteria, and the diagnostic accuracy of PRESS-US was evaluated using ROC curve analysis. Kappa (κ) statistics were used to assess the inter-observer agreement between a less experienced and an expert radiologist.Among the 646 patients, 632 (97.8%) were diagnosed with LM, and 14 (2.2%) had uLMS. The malignancy rates for low-risk and high-risk patients were 0.35% and 13.48%, respectively. The optimal PRESS-US cutoff was 17.5, resulting in an AUC of 89.7% (95% CI, 0.79-1.00), with a sensitivity of 85.7% and a specificity of 87.8%. The inter-observer agreement between a less experienced and an expert radiologist was excellent (κ = 0.811, P < 0.001).PRESS-US provides effective risk stratification for uLMS for radiologists with different levels of experience, with high reliability. Subgrouping high-risk patients helps in better risk stratification.© 2024. Italian Society of Medical Radiology.