Anthropometric and cephalometric orbital measurements were compared in 63 North American Caucasian patients (24 males, 39 females) aged 3 to 29 years who had 13 craniofacial syndromes involving hypertelorism. The hypertelorism, which was diagnosed anthropometrically, was mild in 11 patients, moderate in 25 and severe in 27. The surface intercanthal width was larger than the bony interorbital distance in all patients (mean 12.2 mm). The differences were smaller in mild cases and larger in severe cases. The soft-tissue binocular width was shorter than the bony lateral orbital distance in 53 patients, by a mean of 4.4 mm; in the other 10 patients the two measurements were identical. The hypertelorism was confirmed by cephalometry in 8 of the 11 cases identified as mild by anthropometry (72.7%), 24 of the 25 moderate cases (96.0%) and 25 of the 27 severe cases (92.6%). The abnormally wide surface intercanthal distance was matched by an abnormally wide bony interorbital distance in 57 of the 63 patients (90.5%). In the other six patients (3 with the mild form, 1 with the moderate form and 2 with the severe form) the bony widths were near the upper limit of the normal range (mean + 2 standard deviations).