Over the past decade surgery for sinonasal malignancies encroaching into the anterior skull base (ASB) has evolved from open craniofacial resection to the use of minimally invasive transnasal endoscopic approaches. Using these techniques, ASB reconstruction is most often performed in a multilayer fashion with autologous free grafts (fascia lata or iliotibial tract) which leads to the production of abundant nasal crusting in the postoperative months and discomfort for patients. In carefully selected cases, we propose harvesting a flap from the contralateral nasal septum based on the septal branches of the anterior and posterior ethmoidal arteries (Septal Flip Flap, SFF), which can be rotated to resurface the ASB defect. The exclusion criteria for using the SFF were as follows: cases where the tumour extended to both ethmoid complexes; cases where there was nasal septum or planum spheno-ethmoidalis involvement by the disease; cases of sinonasal malignant tumour with multifocal histology. In our tertiary care referral centre, skull base reconstruction using the SFF was performed in four patients; one was affected by ethmoidal teratocarcinosarcoma, one by persistence of sinonasal undifferentiated carcinoma after radio-chemotherapy, another by olfactory cleft esthesioneuroblastoma and the fourth by ethmoidal squamous cell carcinoma. Successful skull base reconstruction was obtained in all four cases without any intra- or post-operative complications. Post-operatively, nasal crusting was significantly reduced with faster healing of the surgical cavity. No recurrences of disease have been observed after a mean follow-up of 15 months. The SFF can be considered as a safe and effective technique for ASB reconstruction with high success rates similar to those obtained with other pedicled flaps. This flap also ensured a faster healing process with reduction of nasal crusting and improvement in the quality of life of patients in the postoperative period. This technique appears to be a safe and effective option for ASB reconstruction after endonasal resection of sinonasal malignancies in selected cases. Larger case series with a longer follow-up are needed to validate the preliminary results obtained with such an innovative and promising surgical technique.