Purpose Endosteal ossification (EO) of the otic capsule (OC) is a continuous process in the postnatal term. Incomplete ossification is seen as a pericochlear hypodensity on CT. We evaluated the evolution of EO with age using temporal bone CT. The effect of accompanying SNHL with or without radiologically detectable inner ear abnormalities (IEA) also was assessed. Materials & Methods Consecutive temporal bone CT studies of 493 children (986 ears) (mean age: 5.2 years, F/M: 245/248) present in our institution's PACS archive were reviewed. Incomplete EO (iEO) areas were defined and then classified as mild, moderate (Figure A) and severe (Figure B) according to the extent. Results were analyzed with one-way variance analysis and chi-square tests. Results The EO was complete in 387 temporal bones. In the remaining iEO group the most frequent finding was mild focal hypodensity at the fissula ante fenestram (FA) (n =