The problems related to herpes simplex virus (HSV) type 2 infections include: (1) the clinical diseases produced primarily at urogenital sites, but also in extragenital areas, and the frequent recurrences of such infections; (2) the severity of the diseases produced in immunocompromised hosts and in newborns, including a varity of ocular manifestations; and (3) the possible role of the virus in human cancers. The usually sexually transmitted mode of spread of this virus has increased current medical concern with this virus. Although laboratory diagnosis of HSV-2 infection is currently available, we still lack effective preventive or therapeutic means for most clinical forms of the infection. However, the great progress made over the past decade in the molecular, virological, immunological and clinicoepidemiological aspects of HSV are providing the necessary tools to attain this goal.