Acute appendicitis with varicella zoster infection is a very rare event. We report the case of an 18-year-old immunocompetent adult with acute varicella zoster infection and abdominal pain at the right lower quadrant. He had tenderness on the right lower quadrant with defense and rebound. He had no leukocytosis, and abdominal ultrasonography showed an inflammation of the appendix (6.4 mm in diameter) with free fluid of about 25x21x20 mm. We observed the patient with antiviral therapy. On the second day, there was no increment in his physical signs, and on the tenth day of the acute onset of varicella zoster infection, he had no pain; the abdominal ultrasonography revealed no inflammation of the appendix.