In the past few years new human herpes viruses (HHV): HHV-6, -7 and -8 have been discovered. According to the most recent literature, they might have an important role in etiopathogenesis of some dermatological diseases. HUMAN HERPESVIRUS 6: HHV-6 was isolated in 1984 from peripheral blood lymphocytes of AIDS patients and patients with different lymphoproliferative diseases. Up to now, two variants of this virus have been identified, A and B, which differ in genetic, biological and immunological characteristics. The etiological importance of variant A, has not yet been clarified, while variant B is considered to be the major cause of many diseases, such as exanthema subitum in infants. In many cases primary infection is associated with elevated temperature, without rash. HUMAN HERPESVIRUS 7: HHV-7 was isolated in 1990 from activated peripheral blood CD4+ T cells of healthy persons. The virus is ubiquitous and more than 80% of babies and infants are affected. Presence of DNA sequences of this virus in mononuclear cells of peripheral blood, skin and plasma of pityriasis rosea patients, points to possible connection between this illness and HHV-7 infection. HUMAN HERPESVIRUS 8: HHV-8 was first identified in tissue samples of patients with Kaposi's sarcoma associated with AIDS in 1994. DNA virus sequences were also isolated in HIV negative persons with Kaposis's sarcoma. Presence of virus can be established in mononuclear cells of peripheral blood, endothelial cells that cover vascular spaces and spindle cells within skin changes. Modes of transmission are still not clarified. However, HHV-8 was identified in some other dermatological diseases as well.