Glaucoma is one of the leading causes of blindness worldwide. Primary open-angle glaucoma (POAG) is the most prevalent form of glaucoma and has a particularly devastating impact in blacks. In the black American population, POAG prevalence is estimated to be six times as high in certain age groups compared to whites. POAG is more likely to result in irreversible blindness, appears approximately 10 years earlier and progresses more rapidly in blacks than in whites. Racial differences in optic disk parameters have been reported and show that blacks have larger optic disks than whites. This finding is robust and may account for the reported differences in other optic disk parameters. The existence of racial differences in intraocular pressure remains to be demonstrated, as conflicting findings are reported in the literature. Intraocular pressure may actually be underestimated in blacks, perhaps because they have thinner corneas. The prevalence of diabetes and hypertension is higher in blacks than in whites, and although no causal relationship has been established between POAG and each of these systemic diseases, some reports suggest that they often occur together, perhaps through an indirect relationship with intraocular pressure. Compounding the problem, there is evidence that blacks are less responsive to both drug and surgical treatment for POAG. Finally, they often have reduced accessibility to treatment and are less aware of the risks of having POAG. This article provides a comprehensive review of the current knowledge pertaining to POAG in blacks.