Measurement of corneal diameter (CD) in children is pertinent in the diagnosis and monitoring of some ocular diseases, especially anterior segment anomalies and congenital glaucoma (1-3). Nonetheless, normal values of CD in African children are not well documented. The present study therefore sought to establish normative values of CD in full-term newborns and to assess relationship with some birth parameters. Horizontal and vertical CD were evaluated with Castroviejo mm caliper in 1000 eyes of 500 normal full-term babies within the first week of life, in a cross-sectional hospital-based study in the North Central zone of Nigeria. The relationship between CD and perinatal variables were assessed by using univariate and multiple linear regression models. A total of 254 (50.8%) male and 246 (49.2%) female babies were involved in the study. The mean value (mean ± SD) of horizontal CD in the right eyes was 9.87±0.40mm (ranged from 9.00-10.50mm) while it was 9.86±0.40mm in the left eyes (range of 9.00-10.75mm). Mean values of vertical CD was 9.59±0.38mm in the right eyes (range 8.75-10.50mm) and 9.62±0.41mm in the left eyes (range 8.75-10.75mm). There were no significant differences between those of the right and left eyes. The horizontal and vertical CD in males were not significantly different from those in females. The study showed a significant association between birth weight and CD irrespective of baby sex, maternal age, birth length, head circumference and postnatal age. The study also indicated that an increase of 0.36 mm for each kg increase in the birth weight. The results from the present study demonstrate that birth weight is an important independent determinant of CD in newborns. These results would provide useful references for the eye care of newborns in Africa, particularly in Nigeria. Furthermore, the CD values in this study are not consistent with some data from studies in children in other parts of the world. It is therefore plausible to put into account geographical difference when utilizing or interpreting CD values at least in newborns.