Objectives: The purpose of this study was to investigate the characteristics of epidermoid cysts of the external auditory canal (EAC) by analyzing the clinical and radiologic features. Methods:The clinical records were retrospectively reviewed for patients diagnosed with epidermoid cyst of the EAC from March 2004 to December 2013. The epidermoid cysts were diagnosed clinically by endoscopy and microscopy examinations and by temporal bone CT images, and were confirmed by histopathologic examination. Characteristics of epidermoid cysts in bony EAC and cartilaginous EAC were compared. Result:Eight patients had an epidermoid cyst in the bony EAC and nine patients had one in the cartilaginous EAC. Swelling and otalgia were common symptoms, but 47% of cysts were found incidentally. The mean age of patients was 49.6 years (age range, 26-67 years) in the bony EAC cases and 26.1 years (age range, 6-57 years) in the cartilaginous EAC cases. The mean size of the epidermoid cyst was 3.50 mm (size range, 2-7 mm) in the bony EAC cases and 9.55 mm (size range, 2-20 mm) in the cartilaginous EAC cases. The mean follow-up period was 8.3 months (follow-up range, 4-26 months). No complications were reported during or after removal of the cysts, and no recurrences developed during the follow-up period. Conclusion:Comparison of epidermoid cysts of the bony EAC and the cartilaginous EAC revealed that epidermoid cysts of the bony EAC is usually found incidentally, arose in older patients and had smaller size. These characteristics may be due to differences in morphology that the skin of the bony canal is much thinner and more loosely attached to the underlying tissue than the skin of the cartilaginous canal.