Background/aim: To evaluate the diagnostic performance of strain elastography (SE) combined with B-mode ultrasound in distinguishing between idiopathic granulomatous mastitis (IGM) and malignant breast lesions. Materials and methods: Seventy-seven malignant breast lesions and 36 IGM were assessed using B-mode ultrasound and SE. Ultrasonographic findings for all the breast lesions were classified based on the 2013 American College of Radiology Breast Imaging Reporting and Data System (BI-RADS-US), and the SE findings were evaluated based on the strain ratio and a five-point scale. The diagnostic performances of B-mode ultrasonography, SE, and the combination of both methods were compared. Results: Significant differences in strain ratio and elastography scores were found between IGM and malignant breast lesions. When the lesions were assessed with B-mode ultrasound alone, in order to distinguish between IGM and malignant breast lesions, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 94.8%, 66.7%, 85.9%, 85.7%, and 85.8%, respectively. However, when assessed with a combination of B-mode ultrasonography and SE, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 96.1%, 100%, 100%, 92.3%, and 97.3%, respectively. Conclusion: The combination of SE and B-mode ultrasound has better diagnostic performance in the differentiation of IGM and malignant breast lesions than B-mode ultrasonography alone.