Background Seroma formation has become the most reported complication after abdominoplasties. In 2000, progressive tension sutures (PTS) were described and reported to be associated with a seroma rate of 0.1%. Surgeons worldwide use PTS to prevent seroma; however, there are discrepancies in the number of PTS commonly used, starting from five up to 35 sutures. The absence of standardization may cause a lack of seroma prevention, increased surgical time, and general hesitation to perform the technique. Objective To determine whether 11 PTS are sufficient to prevent seroma in abdominoplasties. Methods We performed a single-blind, prospective, comparative, randomized clinical trial of 63 healthy patients from January to December 2017. Patients were divided into groups: group 1, classic abdominoplasty without the use of PTS and drains; group 2, abdominoplasty with the use of 11 PTS and drains; and group 3, abdominoplasty with the use of 22 PTS and drains. The duration of the surgical technique, presence of clinical seroma, number of aspirations, and days to drain removal were evaluated. The Cochran-Armitage, Fisher exact, Kruskal-Wallis, and t tests were used in the statistical analyses. Results PTS reduced the rate of seroma formation to 3.5%. Results showed that there is a benefit in using 11 PTS instead of 22 PTS because using more sutures led to an increased surgical time (30 min vs. 13 min) and possible complications. Compared to patients with PTS, those without PTS underwent more seroma aspirations and delayed drain removal. Conclusions Eleven PTS should be used in classic abdominoplasties.