A neonatal varicella case confirmed early to be infected with varicella-zoster virus (VZV) using PCR analysis was reported. The mother developed an eruption on the following day the patient's birth and was diagnosed as varicella at 3 day of age. The neonate received immunoglobulin and acyclovir (17.5 mg x twice). She was speculated to develop varicella on the 5 to 10 day of age. Eruptions were noted, however, on the 13 day of age, although she was confirmed to be infected with VZV using PCR on the 6 day of age, and her symptoms were much milder than that foreseen. Delay of development and mildness of her symptoms may be attributed to immunoglobulin and acyclovir given on the 3 day of age. PCR method was very useful in determining early that she was infected with VZV.