BACKGROUND: Surgical resection of malignant lip tumors and the reconstruction of extensive lip defects in infants pose significant challenges. We evaluated the effectiveness of the Abbe-Estlander (A-E) flap in repairing upper lip defects in infants following oncosurgery. CASE PRESENTATION: We present two cases of pediatric upper lip malignancies: an 18-month-old infant diagnosed with fibrosarcoma (FS) of the right upper lip (Case 1) and a 19-month-old infant diagnosed with rhabdomyosarcoma (RMS) of the left upper lip (Case 2). Both patients underwent surgical resection of the tumors followed by reconstruction of large upper lip defects using the A-E flap under general anesthesia via nasotracheal intubation. No complications were reported during the procedures. Postoperatively, neither patient received adjuvant chemotherapy. Both patients demonstrated acceptable aesthetic outcomes. Case 1 could use a straw, whereas Case 2 could breastfeed. At the 32- and 18-month follow-up, no recurrences were observed. CONCLUSION: Surgical resection, followed by reconstruction with an A-E flap, is an effective and safe treatment for these tumors in infants. In addition, general anesthesia via nasotracheal intubation is a reliable anesthetic technique for these procedures.