The purpose of the present prospective study was to compare incision and drainage against needle aspiration for the treatment of breast abscesses in lactating women. During the 3-year study period, patients with breast abscesses were randomized 1:1 to undergo either incision and drainage (23 patients) or needle aspiration (22 patients). Ultrasound guidance was not used for any of these patients. Age, parity, localization of abscess, whether or not nipples were cracked, duration of symptoms and lactation, abscess diameter, pus culture results, breast infection history during any previous period of lactation, healing time, recurrence, cosmetic outcome in the case of incision and drainage, and volume of pus removed and number of aspirations needed in the case of aspiration were recorded. The treatment value of each of these techniques was investigated. Student's t-test, Fisher's exact test, a Chi-square test and the Mann-Whitney U-test were used for statistical analysis. In the incision and drainage group all patients were treated successfully, but 1 patient (4%) had a recurrence 2 months after complete healing and 16 patients (70%) in this group were not pleased with the cosmetic outcome. In the needle aspiration group, overall 3 patients were treated with a single aspiration and 10 patients (45%) with multiple aspirations, but 9 patients (41%) did not heal following needle aspiration and subsequently required incision and drainage in addition. No recurrences were observed in the needle aspiration group during the follow-up period. The risk factors for failure of needle aspiration for breast abscesses were abscesses larger than 5 cm in diameter, unusually large volume of aspirated pus, and delay in treatment. In conclusion, breast abscesses smaller than 5 cm in diameter on physical examination can be treated with repeated aspirations with good cosmetic results. Incision and drainage should be reserved for use in patients with larger abscesses.