The purpose of this study was to evaluate the diagnostic utility of sonoelastography in differentiating benign from malignant non-palpable breast lesions. A total of 293 BI-RADS 3-5 (Breast Imaging Reporting And Data System) impalpable breast lesions in 278 women was evaluated with B-mode ultrasound (US) and subsequently with sonoelastography (SE) before performing US-guided biopsy. Among the 293 lesions (size up to 2 cm), 110 (37.5%) were histologically malignant and 183 (62.5%) benign. Lesions that were malignant or showed atypical ductal hyperplasia were referred for surgical excision, as well as 32 benign lesions showing discordance between US/SE results and histology. All other benign lesions had US follow-up at 6/12 months, showing stability. Overall performance of SE was lower than US, with sensitivity and specificity of 80% and 80.9%, respectively, for SE as compared with 95.4% and 87.4% for US. Statistical analysis showed no improvement in the joint use of SE and US over the use of US alone, whose performance, however, was very high in our study. SE is a simple, fast and non-invasive diagnostic method that may be a useful aid to US for less experienced radiologists in the assessment of solid non-palpable breast lesions, especially BI-RADS 3, where specificity was higher (88.7%).