This study aimed to study the mastoid air cells diseases and their complications using spiral CT, it was conducted in Alfaisal Specialized hospital and Ibn Elhaitham Diagnostic center in the period between September 2012 to January 2013, Hundred patients of different ages and different genders who were suspected of having mastoid air cells pathologies underwent Spiral CT scan of their temporal bones using 4MDSCT (Toshiba medical system),then the scanning was done with collimation of (1-2) mm, 2mm slice thickenings ,120 Kvp ,160 MA and 1 second rotation time. after that The results were confirmed that the mastoid air cells diseases were very common and they had serious complications, (The diseases of mastoditis and mastoditis with CSOM had higher frequency (83 patients among 100 patients).and they had pathological changes of anatomical structures of the temporal bones which contains organs of hearing and balance). Finally the study has found that Spiral CT scan is an effective imaging modality in studying of mastoid air cells diseases and their complications. Also it was more affective to explain the complex anatomical structures of the temporal bones and to know the pathological changes within it.