To evaluate the diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant breast lesions.Forty patients with positive diagnoses at mammography or breast ultrasound were included in this study. Patients were imaged with dynamic contrast enhanced MRI and DWI before biopsy of their breast tumors. Apparent diffusion coefficient (ADC) map was utilized to select the region of interest (ROI) for ADC calculation. DWI was performed using three sets of b value (0, 400, and 800s/mm2).The final analysis comprised 40 breast lesions, 18 of which were malignant and 22 were benign. Significant results were obtained between ADC values of benign and malignant lesions (p<0.001). The cut-off ADC value for benign and malignant lesions was 1.25×10–3mm2/s.The present study provides consistent evidence to support DWI as a diagnostic tool for breast lesion characterization and as a useful adjunct to standard breast MRI protocols in aiding the diagnosis of breast cancer.