The size of the cornea is important in the diagnosis of primary infantile glaucoma. Reference values regarding eyes of premature infants are scarce. Such data are of special importance in areas such as the Middle East where infantile glaucoma is common and often evident already at birth. The authors have measured the horizontal corneal diameter of the eyes of 127 premature Saudi infants with a gestational age between 23 and 36 weeks and a birth weight ranging from 540 g to 4720 g. The corneal diameter ranged from 7.75 mm to 10 mm. The smallest diameter (7.75 mm) was found in an infant with a gestational age of 23 weeks and having a birth weight of 520 g. The largest diameter (10 mm) belonged to two infants with a gestational age of 34 and 35 weeks and a birth weight of 2250 g and 2240 g respectively. Corneal diameter was positively correlated (p < 0.001) with gestational age and birth weight. Graphs depicting the regression line of corneal diameter on gestational age and of corneal diameter on birth weight together with the 95% confidence limits for individual values are provided for reference.