Background/Aims: Minimizing bleeding during transnasal resections of sinonasal tumors is imperative for optimizing visualization and decreasing complications. The purpose of the present study was to determine whether radiofrequency coblation decreases blood loss during endoscopic tumor removal. Methods: Sinonasal/skull base tumors treated in 2008 with endoscopic techniques were reviewed. The data collected included demographics, histopathology, technique, duration, complications and estimated blood loss (EBL). Full operative videoendoscopy was available in all cases and scored by the authors using the 11-point Wormald surgical field grading scale. Results: Twenty-three patients (average age: 46 years) with sinonasal or skull base tumors treated with transnasal endoscopic techniques were identified. Coblation was used in 10 cases. The sinus/skull base tumors included were esthesioneuroblastoma (n = 6), melanoma (n = 3), squamous cell carcinoma (n = 3), inverted papilloma (n = 3), adenocarcinoma (n = 2), intracranial dermoid cyst (n = 2), adenoid cystic carcinoma (n = 1), craniopharyngioma (n = 1), fibromyxosarcoma (n = 1) and undifferentiated carcinoma (n = 1). The use of the coblation device was associated with a significant decrease in all categories including EBL (350 vs. 1,000 ml; p = 0.0001), EBL per operative time (66 vs. 166 ml/h; p = 0.0001) and Wormald grade (3.3 vs. 6.4; p = 0.0001). Conclusion: Radiofrequency coblation significantly decreased blood loss during endoscopic tumor removal and is a useful tool in the armamentarium of the endoscopic skull base surgeon. © 2010 S. Karger AG.