Background : Data on the frequency of Herpes Zoster are sparse, especially in inpatients Objective : The purpose of this study was to elucidate the epidemilogy and the clinical characteristics of herpes zoster in inpatients. Methods : During a 3-year-Period from Jan. 1991 to Dec. 1991, 157patients with herpes zoster were evaluated in regard to annual, monthly and seasonal incidence age incidenee and sex ratio. Patients with herpes zoster were further assessed concerning associratel conditions, dermatomic distributions and complications. Results : 1. The annual rate ranged from 2.6% to 3.3% (mean 2.8%) and the ratio of male to female was 0.85: 1. 2. There were no marked manthly of spasonal differences in herpsoster, ranging from 4.5% to 10.8% and 21.7% to 31.2%, respectively. 3. Herpes Zoster was seen most frequently in the 50-59 year age group(27.4%) 4. The dermatomic involvernent of herpes zoster was most freqer t of thoracic dermatome(51.6%) and others were trigeminal(19.1%), cervical(13.4%), lumbar(6.4%), sacral(5.7%), facial(1.9%) and generalized(1.9%). 5. The frequency of associated conditions in herpes zoster was in d scending order, hypertension, tuberculosis, diabetes mellitus, malignancy, SLE, gastric ulcer, chronic renal failiure, rheumatoid arthritis, idiopathic pulmonary fibrosis. 6. The most common complication of herpes zoster was postheret c neuralgia and others were ophathalmologic complications, secondary bacterial infection, keloicl, formation, generalized varicelliform eruption, recurrent herpes zoster. Conclusion : Herpes Zoster is a major problem in the Department of Dermatology, especially in inpatients, (Kor J Dermatol 1994; 32(4): 583-590)