The objectives of this study are to estimate the total cost and the unit cost of Chun District Hospital on HIV/AIDS patients, and to assess the cost burden on this hospital of HIV/AIDS patients. The sample size of both HIV/AIDS and non-HIV/AIDS patients are 92 cases for each group. Data used for calculating provider's cost is obtained from surveying, interviewing health personnel and caregivers, observing activities, and retrospective cata in 1992. Cost is then calculated by inputs, and classified as recurrent and capital cost. This study also Civides cost by health service activities i.e. treatment, MCH, health promotion, day care, home health care, and einer services. The result of this study indicated total cost of hospital in 1998 was 21,468,724 Baht (US$ 596,353). The total cost of hospital per population was 447 Baht (US$ 12). Cost of HIV/AIDS patients was equal 16.4% of total cost. Additional cost of the hospital in 1998 was 47.8% higher than its cost in 1992 at constant price before AIDS spreaded into community, and specific additional cost for HIV/AIDS patients was 16.4% of total cost. Activities provided for HIV/AIDS patients were day care, health promotion counseling, home health care, and AZT treatment for infected pregnant women and children to prevent AIDS transmission. This study also found that a significant increased in hospital cost was due to high labor cost and high medical cost. Since the additional cost of hospital increased but the number of patients was about the same, it implied that utilization might be relatively low and services was not efficient or the type and quality of care had significantly changed over time. The unit cost for HIV/AIDS in-patients were higher than non-HIV/AIDS in-patients by 3.7 times. The unit cost for HIVIAIDS in-patientswas 649 Baht (US$ 18) per day or 3,692 Baht (US$ 103) per patient. For non HIV/AIDS in-patients, unit cost was 531 Baht (US$ 15) per day or 1,000 Baht (US$ 28) per patient. The unit cost for HIV/AIDS out-patients and non-HIV/AIDS out-patients were 153 Baht (US$ 4) and 144 Baht (US$ 4) respectively. The above findings is important for managing the cost of care for HIV/AIDS patients in the public hospital and for allocating government budget to specific services. Standard of treatment should also be promoted by the government and systematically implemented to improve technical efficiency, quality of care, qualified health personnel, good treatment, and health promotion in order to achieve the goal of good health at low cost.