Although changes in lateral abdominal wall musculature after posterior component separation with transversus abdominis release have been investigated, the effects of endoscopic subcutaneous anterior component separation (ES-ACS) on postoperative muscle anatomy have not been evaluated. The purpose of this study was to evaluate changes in the lateral abdominal muscles after ES-ACS.Computed tomography (CT) images of patients who underwent ES-ACS were retrospectively evaluated. Lateral abdominal wall thickness and external oblique displacement were measured at the level of fixed retroperitoneal structures. Measurements on the ES-ACS side were compared with those on the contralateral undivided side or with preoperative images in patients with bilateral procedures.Fifteen patients met the criteria for study inclusion. Most patients (n = 13, 86.7%) underwent unilateral ES-ACS. The most commonly performed procedure was laparoscopic intraperitoneal onlay mesh-plus hernia repair (n = 12, 80.0%; the remaining patients underwent open repair). The Mean defect width was 8.4 cm (range 6-15 cm). There was no difference in the thickness of the lateral abdominal musculature between ES-ACS and undivided sides. There was a significant lateral displacement of the external oblique muscle from the lateral edge of the rectus abdominis on the ES-ACS side (mean distance 3.7 cm; p = 0.0006). No midline hernia recurrences, iatrogenic linea semilunaris hernias, or lateral eventrations were observed during a mean follow-up period of 2.6 years (range 0.5-7.4 years).ES-ACS resulted in no atrophy of the lateral abdominal muscles in long-term CT follow-up. The procedure is a safe and effective adjunct to complex hernia repair in selected patients.