Purpose-To compare the optic disk size of African, Asian, Caucasian, Hispanic and Filipino American patients in a multiethnic glaucoma practice.Patients and Methods-576 eyes of 319 patients who had consecutively received Heidelberg Retinal Tomography II (HRT) from February 2006 to October 2007 in a glaucoma clinic that met inclusion criteria were included. The five ethnic groups represented were Caucasian (n = 215, 37.3%), Asian (non-Filipino) (n = 178, 30.8%), African (n = 67, 11.6%), Hispanic (n = 66, 11.4%) and Filipino American (n= 50, 8.7%). The relationships of optic disk size (Global Disc Area) with race, age, gender, diagnosis, central corneal thickness (CCT), spherical equivalent refraction (SE), and cylindrical refraction were evaluated using multivariate regression analysis adjusting for confounders.