Background: The morphometric analysis of the internal acoustic canal (IAC) has important relevance in microneurosurgery, diagnostic neuroradiology, otorhinolaryngology, neuroanatomy and forensic medicine. It is essential to establish the anatomical bases for microsurgery of the cerebellopontine angle and vestibular schwannoma. The literature is replete with numerous ranges of the dimensions of the IAC from studies conducted amongst Caucasians. Available studies of the IAC in this sub-region are limited and little is known about gender and racial variations that are peculiar to the Nigerians. Hence, studies focusing on the morphometry of the IAC are quite relevant in this sub-region. Objectives: The aim of this study was to use computed tomographic (CT) scan to determine internal acoustic canal (IAC) variables viz: the IAC opening diameter, the mid canal diameter, the fundus diameter and the length of the IAC, length of the posterior wall and to determine the location and shapes of the IAC. The study also determined the variation of the dimensions with age and gender, as well as intra-individual variability between right and left IAC dimensions. Methodology: This was a prospective cross sectional descriptive study to ascertain the anthropometry of the right and left IAC in Nigerians. CT images of IAC of 300 male and female subjects aged 2 to 80 years were obtained in the canthomeatal plane with 1.25mm bone window reconstruction. Measurements obtained included the internal acoustic meatus opening diameter (OD), the mid canal diameter (MCD), the diameter of the fundus (FD), the IAC length (L), and length of the posterior wall (PL). The linear distance of the internal acoustic meatus to the posterior lip of the sigmoid sulcus (PS) and shapes were also determined. Results: 300 subjects were analysed. The pattern (measurements in mm) showed mean OD: 7.16±0.15 with a range of 3.95-11.20; mean L: 11.16±0.2 with a range of 7.55-16.90; mean PL: 9.18±0.19 with a range of 5.05-15.0; mean MCD: mean 4.15±0.08 with a range of 2.55-6.10; mean FD: 2.42±0.06 with a range of 1.20-4.7; mean PS: 34.97±0.38 with a range of 24.55-47.75. The mean L, PL, PS displayed significant increase with age. There was no significant variability between right and left IAC variables. Males had significant higher mean OD, MC and FD compared with females. Females had a higher mean L, PL and PS. Two dominant shapes of the IAC: cylindrical 50%, funnel 43%, were observed. Conclusion: This study identified significant modest increase of mean L, PL, and PS with age while the mean OD, MCD and FD did not vary significantly with age. There was no significant intra-individual variability between right and left IAC variables. The IAC displayed sexualdimorphism with males having higher mean OD, MCD and FD. The mean PL 9.18mm should be considered in drilling the posterior wall of the IAC medial to lateral in the retrosigmoid surgical approach to the IAC in order to avoid entry into the bony labyrinth. Cylindrical and funnel shaped IAC constituted the dominant forms.