The significance of the increase in intraocular pressure (IOP) on upgaze in the diagnosis of Graves ophthalmopathy and its normal range are controversial. The authors measured the increase in IOP on upgaze in 69 hyperthyroid patients with Graves disease, diagnosed at 1 month to 15 years previously, to assess their clinical, laboratory, and ophthalmic state. Ninetyseven healthy subjects served as controls. The distribution of increase in IOP on upgaze values in 46 patients with noninfiltrative ophthalmopathy (classes 0 to 1) was the same as in the control group. The 23 patients with infiltrative ophthalmopathy (classes 2 to 4) had increased frequency of higher increases in IOP on upgaze values compared with the other two groups. However, because of considerable overlap, increase in IOP on upgaze was not discriminatory between the groups. Increase in IOP on upgaze correlated positively with the severity of exophthalmos. There was no correlation among age, sex, time since diagnosis, thyroid functional state, and drug therapy. The authors conclude that an increase in IOP on upgaze is a normal finding augmented by Graves infiltrative ophthalmopathy. It has no diagnostic advantage over the simple clinical signs of ophthalmopathy.