Background:In this article, we discuss a new technique of pectoralis major muscle volumization using ultrasound-guided fat grafting, considering a new surgical criterion that allows for larger volumes.Methods:We present a retrospective observational descriptive study, which included men who underwent body contouring surgery during 2022-2023. As part of the study, measurements were taken before, immediately after, and at 3 months after surgery. Data were stored in a database and analyzed using SPSS statistical software, v23.0.Results:The average age was 34.8 years [+/- 8.2] and when evaluating the cases based on their body mass index, we found an average body mass index of 28.2 kg/m2 [+/- 1.9]. When evaluating the paired differences between initial depth of pectoralis major-transoperative depth of pectoralis major, transoperative depth of pectoralis major-postoperative depth of pectoralis major at 3 months, and initial depth of pectoralis major-postoperative depth of pectoralis major at 3 months using the Student t statistic for related samples, statistically significant differences were obtained (P = 0.001). This is a preliminary short-term study revealing a new approach to volumizing the pectoralis major muscle and requires long-term follow-up.Conclusions:The technique allows for an increase in muscle thickness. Measurements were taken immediately after infiltration and at 3 months, observing the presence of the fat graft and the increase in volume. In the future, it is important to perform long-term follow-up. No adverse events occurred during the study.