We conducted a prospective, randomized study to evaluate the necessity of drainage after uncomplicated thyroid surgery. The subjects were 135 patients who underwent thyroid surgery between September 2002 and February 2004. The patients were randomized into two groups according to whether drains were inserted at the time of surgery. Group 1 consisted of 68 patients with drains and group 2 consisted of 67 patients without drains. The indications for surgery, procedures performed, local complications (such as infection, seroma, and bleeding or hematoma), necessity for reoperation, and hospital stay were recorded. There were 110 (81.5%) women and 25 (18.5%) men, with a median age of 46.9 +/- 12.5 years. The mean hospital stay was 2.6 +/- 1.0 days in group 1 and 1.3 +/- 0.7 days in group 2 (P = 0.001). Local complications developed in five (7.3%) patients from group 1, as wound infections in two (2.9%), seroma in one (1.5%), and hemorrhage in two (2.9%); and in two (3%) patients from group 2, as seroma in one (1.5%) and hematoma in one (1.5%). Both of the group 1 patients with postoperative hemorrhage required reoperation within 8 h after initial surgery. The hematoma in the group 2 patient was treated successfully with needle aspiration. These findings suggest that the routine use of drains may be abandoned in uncomplicated thyroid surgery, since serious postoperative bleeding rarely occurs and hematomas can be treated by needle aspiration if drains have not been placed. Furthermore, the use of drains prolongs hospital stay and increases the risk of infection.