HIV/AIDS is a global pandemic with critical demographic, economic, and social implications. The pandemic is widespread in poor regions of the world, including Southeast Asia where its long-term effects are potentially catastrophic. Despite the major impacts of the epidemic being already felt at the household level in many countries, a lack of recognition of the socioeconomic determinants of HIV infection and the economic and social impacts of HIV/AIDS and their relationship with poverty persists. This is due in part to the lack of systematic studies at the household, community, sectoral, and macro levels. The thesis describes a 'vicious circle' between HIV/AIDS, poverty and high-risk behaviour at the individual level. In the poverty-HIV/AIDS cycle, HIV-infected individuals are especially vulnerable to poverty, the poor are more likely to engage in high-risk behaviour such as commercial sex work, and high-risk behaviour in turn makes people susceptible to HIV infection. The thesis examines whether rural Northeast Thailand exhibits characteristics that support the existence of such a cycle. Four key relationships are considered and tested: (i) the relationship between previous HIV infection and current wealth or poverty; (ii) the relationship betweem wealth or poverty and HIV/AIDS knowledge; (iii) the relationship between previous wealth or poverty and current HIV infection; and (iv) the relationship between previous migration and current HIV infection. All four relationships are shown to hold using survey data from Khon Kaen province in Northeast Thailand. Poverty is shown to increase susceptibility to HIV infection, and HIV/AIDS is shown to reduce wealth and hence increase poverty. Under the circumstances, the hypothesis that rural Northeast Thailand exhibits characteristics that would suggest the existence of a poverty-HIV/AIDS cycle cannot be rejected. This thesis also provides several key contributions to the literature on HIV/AIDS and poverty. First, it provides quantitative and qualitative empirical analysis of the impacts of HIV/AIDS on households in a moderately affected region of Thailand. Second, it provides empirical analysis both on whether wealth and poverty affect the risk of HIV infection, and whether HIV infection affects wealth and poverty. The results from this thesis also provide significant empirical evidence of the importance of rural-urban migration in the spread of HIV in Asia. Finally, the thesis investigates the potential effects on the poverty-HIV/AIDS cycle of an ongoing socio-economic intervention, namely breaking the poverty-HIV/AIDS cycle via intensive rural development.