Background: Separating benign from malignant soft-tissue masses often requires a biopsy. The objective of this study was to assess whether shear-wave elastography (SWE) helped to separate benign from malignant soft-tissue masses. Methods: In 2015–2016, we prospectively included patients with soft-tissue masses deemed by our multidisciplinary sarcoma board to require a diagnostic biopsy. All patients underwent ultrasonography (US) followed by SWE to measure elasticity. We compared benign and malignant tumors, overall and after separating tumors with vs. without a fatty component. The biopsy findings, and surgical-specimen histology when available, served as the reference standard. Results: We included 136 patients, 99 with non-fatty and 37 with fatty soft-tissue masses. Mean elasticity and T/F values were significantly lower for the benign than the malignant soft-tissue masses in the overall cohort (30.9 vs. 50.0 kPa, P=0.03; and 2.55 vs. 4.30, P=0.046) and in the non-fatty subgroup (37.8±31.9 vs. 58.9±39.1 kPa, P=0.049 and 2.89±5.25 vs. 5.07±5.41, P=0.046). Data for fatty tumors were non relevant due to lack of conclusive results. By receiver operating characteristics curve analysis, a T/F cutoff of 3.5 had 46% sensitivity and 84% specificity for separating benign and malignant soft-tissue masses. Conclusions: SWE had good specificity for separating benign from malignant soft-tissue masses.