PURPOSE: To evaluate the ultrasonographic features of nonlactiferous breast abscess. MATERIALS AND METHODS: We retrospectively reviewed ultrasonograms of 21 cases with surgically and clinically proved nonlactiferous breast abscess. The cases included 17 cases of acute or chronic inflammation and 4 cases of tuberculosis. RESULTS: Location of the lesion was subareolar in 15 cases and peripheral in 6. Mean anteroposterior/transverse diameter ratio was 0.49. Internal echogenicitiy of the lesion was variable, with heterogeneous mixed-echoic echotexture in 18 cases and homogeneous hypoechoic in 3. Margin of the lesion was irregular in 18 cases(85.7%) and posterior sonic enhancement was observed in 17 cases(81%). There were also noted obliteration of adjacent superficial fascia, localized skin thickening, and sinus tract or ductal ectasia in 19(90.5%), 9 (42.9%), and 9(42.9%) cases respectively. CONCLUSION: Major ultrasonographic findings of nonlactiferous breast abscess was subareolar located, variable shaped mass with posterior enhancement. Additional findings were fistular formation, loss of superficial fascia, and axillary lymphadenopathy.