Herpes simplex virus (HSV) is a common cause of viral encephalitis. Herpes simplex encephalitis (HSE) remains one of the most devastating infections of the central nervous system despite available antiviral therapy. Herpes simplex encephalitis (HSE) typically presents with acute neurological changes and the initial cerebrospinal fluid examination is nearly always abnormal. However, these clinical findings are not pathognomonic because numerous other diseases in the central nervous system can mimic HSE. In the current era, the diagnostic gold standard is the detection of HSV DNA in the cerebrospinal fluid by polymerase chain reaction. Cystic encephalomalacia is uncommon after HSE. In addition it can effect bilateral hemisferic structre and characterised with cystic cavite and gliosis. In this study, it was presented a rare case cystic encephalomalacia occurred after HSV encephalitis.