Background: Minimally invasive ablative techniques in the treatment of breast tumor has become popularly in recent years. Methods: We analyzed gray-scale and contrast-enhanced ultrasound (CEUS) features of 205 microwave ablated breast benign lesions from 182 consecutive patients, compared with magnetic resonance imaging (MRI) and histopathology findings. The follow-up was implemented at 3, 6 and 12 months after the ablation treatment. Results: Before the MWA, the mean of largest diameter and volume of the lesions were 14.41 +/- 6.54 and 3,224 +/- 961 mm(3), respectively. However, those of the lesions respectively were 8.48 +/- 6.30 and 2,116 +/- 732 mm(3) one year after the treatment. The longest diameter and the volume of the ablative lesions were gradually decreased 3, 6 or 12 months after the MWA. 44 (/205, 21.5%) ablative lesions were disappeared one year after the MWA. One hundred and forty-two (/205, 69.3%) ablative lesions presented a hypoechoic halo surrounding it on gray-scale US after the MWA. The success rate of the MWA treatment in the benign breast lesion was 87.32% and 82.93% evaluated by CEUS and enhanced MRI, respectively. During the ablation, no patient had serious complications, such as hemorrhage, serious pain and fat necrosis, etc. Conclusions: Microwave ablation was a safe and efficient method in the treatment of the benign breast tumors. CEUS and enhanced MRI could accurately assess whether the MWA treatment is effective.