This chapter provides taxonomy, description of the agent, epidemiology and transmission, clinical significance, direct detection, isolation procedures, identification and typing, serologic tests, and antiviral susceptibilities of Herpes Simplex viruses (HSVs) and Herpes B virus. HSV infections occur worldwide with no seasonal distribution. Most HSV‐1 infections are acquired early in childhood as subclinical or unrecognized infections. Young children may present with classic primary HSV‐1 infection characterized by gingivostomatitis, fever, and marked submandibular lymphadenopathy. Herpes B virus is similar to HSV in terms of genome size and structure and in terms of virion morphology. Herpes B virus can be cultured in monkey kidney and chicken embryo cells. Detection of virus in patient samples without an intervening culture amplification step provides the most rapid diagnosis. Serodiagnosis of herpes B virus infections has been complicated by extensive cross‐reactivity with HSV‐1 and HSV‐2.