OBJECTIVES: To determine the incidence of zoster- associated symptoms, as well as the impact of zoster on pain, quality of life, work loss, health care utilization and direct health care costs among 180 Thai patients seeking medical care for herpes zoster. METHODS: Study design: prospective observational study conducted in 7 hospitals in Bangkok and vicinity, Thailand Study population: patients recently diagnosed herpes zoster, and meeting at least one other criterion, as follows: aged ≥50 years; aged ≥20 years with HIV-infection or receiving chemotherapy. All patients were scheduled for 5 visits (i.e. at Day1, Day7, Month1, Month3, Month6) for questionnaire based interview to determine zoster-associated pain (Zoster Brief Pain Inventory questionnaire), quality of life (EUROQOL 5-dimension questionnaire), work and productivity (multi-response questionnaire), and health care utilization and cost. Statistical analysis: Descriptive statistics and Spearman rank correlation coefficients were used.   RESULTS: Of 180 patients, whose mean (SD) age was 58.9 (13.82) years, 138 (76.7%), 34 (18.9%), and 8 (4.4%) were age ≥ 50 years, HIV-infected and immunosuppressed, respectively. Thirteen (7.2%) and 35 (20.6 %) patients had zoster ophthalmicus and post-herpetic neuralgia (pain that persisted beyond 3 months of illness), respectively. Peak QoL lost was observed during the first week of study and declined thereafter. Correlations between worst-pain scores and QoL were moderately high, r=0.54. Of those 77 working patients, 57 reported that they were absent from work, either entired day or part of day, during zoster illness. Thirty patients reported sick leave and the median number of days off was 5.5 (1-52) days. Most patients required only 2 OPD visits for zoster illnesses. Other health care services requirement included emergency-room visits (n=2), ambulance services (n=3), or hospital admissions (n=7). The mean (SD) direct health care cost was 3,083.39 (5047.03) Thai Baht. CONCLUSIONS: Herpes zoster causes a significant burden among those who develop it.