Epidermoid cyst in bony wall of external auditory canal (EAC) is a very rare pathologic condition. In addition to its extreme rarity, its positional proximity to temporomandibular joint(TMJ) might lead to clinical misdiagnosis as TMJ disorders, especially when it is accompaniedby temporomandibular disorders-like symptoms. In this article, we report a patient with epidermoidcyst in anterior bony wall of EAC, which was misdiagnosed as TMJ disorder because theleft TMJ pain aggravated during mastication.