Background objectives: Previous research has documented the substantial household economic impact of a recent HIV/AIDS death. There is limited information about the household economic impact of HIV/AIDS illness or forms of coping strategies used by households with different levels of available care and support services. The study aimed to understand the economic impact of chronic adult HIV morbidity and examine how households cope with the situation. Specifically the study aimed to: 1) explore the coping strategies used by households to reduce the impact of chronic HIV/AIDS, 2) document the levels and forms of utilisation of support and health services by households affected by chronic HIV/AIDS, 3) explore whether the availability of services influences the household economic impact of chronic HIV/AIDS morbidity, and the coping strategies used by households, 4) explore the implications of the findings for policies to mitigate the impact of HIV/AIDS on households and communities. Study design and setting: The study was conducted in Phayao province in Northern Thailand where people of this province were highly affected by HIV illness and death. Two study districts were identified: Mueng had active support services and Pong had less active services. Within each district, 9 villages were randomly selected and within each village a mapping survey of all households was conducted to identify 'case household' (household with chronically ill adult (CIA)) and 'control household' (household where there was no history of chronic illness in the past 6 months or household member aged 15-49 years died from chronic diseases). In each district, 150 case and 150 control households were selected for interview conducted by trained interviewers in Thai. Outcome indicators: The main outcome indicators were: the reported availability and use of support services, medical care expenditure in the past six months, source and level of income, coping mechanism of households e.g. saving and borrowing money, selling of assets and transfer money. The main outcome indicators compared among case households between two districts were the direct and indirect costs associated with having CIAs, the reported loss of income and how care of children and the elderly was affected by chronic illness. Data entry and analysis: The data were entered twice and cleaned before the final analysis was conducted. Descriptive statistics were used to obtain the demographic and household socio-economic profile and estimates of the socio-economic impact. Tabulations, t-test, bivariate and regression analyses were used to identify factors associated with impact and the coping mechanisms of households. Results: The case and control samples were relatively comparable. Support services in the last six months were more available in Mueng than in Pong in either case or control households. Regression results suggest that having a CIA significantly reduced the reported use of all services. A significantly lower percentage of household members aged 15-59 years were employed in case households than in control households in both districts. Case households as well as households in Mueng were less likely to have cash income and among households with a cash income HIV/AIDS morbidity did not impact on the per capita household cash income and this was confirmed from the regression analysis. About one-third of all households reported having savings. Two-thirds of case households in Mueng and half of case households in Pong reported using their savings for health care cost. Case households in both districts had a lower value of assets per capita than control households. About half of all households reported being in debt. Case households reported being in debt less than control households. Case households borrowed for daily consumption and health care while control households borrowed for investment. To cope with HIV illness, case households used their savings, sold their assets, cut their consumption and obtained transfer-in and supports from extended family members for care for children and the elderly. Various strategies were used to maintain family productivity including increasing family members' workload, hiring labours and withdrawal of children (especially girls) from school. The study documented 324 CIAs from 300 case households. Caregivers who took care of CIAs at home were parents, spouses or children of the CIA, with over a quarter of the adult care-givers stopping working and almost three quarters of child caregivers stopping going to school. In the past 6 months, the average health care expenditure in case households was significantly higher than in control households in both districts and the case households in Mueng reported significantly lower health care expenditure than in Pong. The percentage of case households in Mueng that paid health care expenditure by households was half of that in Pong. This was supported by the proportion of health care card usage among the case households in Mueng which was significantly higher than those in Pong. There were 24% and 39% of case households in Mueng and in Pong reported having experienced being discrimination against. Conclusions: This thesis highlights how chronic HIV morbidity impacts on household income, savings and assets. The study has illustrated how chronic HIV/AIDS morbidity impacts substantially on household labour supply and family production. This impact in case households was relatively more than in control households. Our findings suggest that the Free Medical Program for the poor under the Ministry of Public Health did not reach the poorest section of the case households in Pong. It is important that methods to increase coverage to these vulnerable groups are identified. Case households in Mueng appeared to be less affected by consumption reduction than case households in Pong. This might be because the case households in Mueng had, on average, higher incomes, higher value of assets, lower medical care cost and lower income loss than those of case households in Pong. Our study therefore confirms that the poor families with chronic HIV/AIDS morbidity suffer more consumption reduction. The study has important policy implications to ensure that households can support themselves and meet their medical care needs without jeopardising the wellbeing and future of other household members.