OBJECTIVE To discuss the clinic presentation,imaging characteristics and surgical management of the external auditory canal cholesteatoma (EACC) with invasion of the tympaniccavity and the mastoid. METHODS This was a retrospective study including the clinical data of 14 cases of EACC invading tympanic cavity and mastoid from 1998 to 2003 . RESULTS All 14 cases showed different bone erosion in the four walls of external auditory canal with extention to the mastoid . Pars flaccida perforation were found in 4 cases with invasion of the cholesteatoma into the tympanic cavity, the ossicular chains were compressed or destroyed. The bony mastoid segment of facial canal was destroyed in 3 cases . Cerebral plate destruction and congenital stenosis of external auditory canal were found in one case respectively. According to the extent of disease, modified radical mastoidectomy was performed in 8 cases and radical mastoidectomy in 5 cases , meatoplasty in one case. The post-operative hearing of 10 cases with intact ossicula chains were normal.One case with compression,shift of ossicules also got normal audition after the operation. The hearing threshold of the air condition in 3 cases with ossicular disruptions got 15 to 20dB of improvement among the language frequency after reconstruction of ossicular chain. The 14 cases were followed-up from 18 months to 5 years and no recurrences were found. CONCLUSION The exact etiology of EACC still remains unclear. There is some difficulty in diagnosing external auditory canal cholesteatoma (EACC) invading the tympanic cavity and the mastoid because of its untypical clinic presentation . High-resolution temporal bone CT scan could help to find out the primary lesion and determine the range of the pathological changes, and choose the proper surgical approach.