From May 1981 to May 1984, 90 pediatric patients underwent liver transplantation and 65 patients survived as of May 1986. Two of the nonsurvivors died with complications related to clinical varicella. Of these 67 patients (65 survivors and two nonsurvivors who died of varicella-related causes), 51 patients were determined to be varicella susceptible. Clinical disease developed in no patients with serologic evidence or clinical history of varicella prior to transplantation. Eighteen susceptible patients were exposed and received zoster immune globulin and varicella did not develop. Clinical disease developed in eight patients despite zoster immune globulin, although one patient received it 96 hours after exposure. Six patients received no zoster immune globulin and clinical varicella developed. In all, varicella developed in 14 patients. Thirteen were admitted to the hospital and treated with intravenous acyclovir. Of those treated, two died of causes related to complications of varicella. The remaining patients treated with acyclovir had mild disease. The one patient not treated with acyclovir also had mild disease. We conclude that patients contracting varicella after liver transplantation while receiving maintenance immunosuppressive agents should be treated with intravenous acyclovir. Generally, when treated with acyclovir while receiving maintenance immunosuppressive drugs, these patients have mild clinical disease. Patients recently treated with high-dose prednisone and cyclosporine may have severe clinical disease resulting in death.