['Detailed studies of cochlear morphology can guide our approach to cochleostomy and electrode insertion to optimize neuronal and hair cell preservation and ultimate electrode location.', 'Normal developed cochleae from 124 cochlear implant candidates were studied. We performed morphometric analysis of the right cochleae in all subjects based on computed tomographic data. The length and width of the cochlear base, the angle between the first and second turn of the cochlea, and the cochlear orientation within the cranial base were measured and compared across age groups. In cochlear implant candidates with underdeveloped cochleae (n = 7), we performed similar measurements and assessed the modiolar inlet area on 3D volume rendered images.', 'The birth to 1 year and 1- to 2-year age groups showed insignificant differences in the lengths and widths of the cochlear base, although variability was considerable, and a significantly wider angle (from the midsagittal line) than that of the older age groupings (p < 0.05). For underdeveloped cochleae, the length and width of the cochlear base were significantly smaller and angled between the first and second turn differed from the normal developed group. The modiolar inlet also was significantly smaller in the underdeveloped cochleae compared with normal cochleae.'] Do cochlear coiling pattern and orientation differences in cochlear implant candidates?