HIV epidemics in Asia have been mainly concentrated among certain population groups such as injecting drug users, sex workers and their clients and men who have sex with men (MSM). HIV risk has also been associated with labour migrants and their partners. Many of the people at risk through these behaviours are very poor, and this raises the question that poverty and social deprivation may be underlying factors that drive the adoption of risk behaviours and can be regarded as ‘determinants’ of vulnerability to HIV infection in Asia. The study presents some observations of the socioeconomic pattern of HIV spread in Asia, using country-level and household-level data. The discussion then draws tentative conclusions about what is known concerning the mechanisms influencing the risk of HIV acquisition in Asia and what they might imply for programme design and policy. In summary, the data presented here do not support the hypothesis that HIV epidemics in Asia are primarily driven by poverty and social deprivation, though sex inequality and education for women and girls are strongly associated factors. There is clearly a multidimensional relationship between the risk of HIV infection and a host of underlying social and cultural factors that confound any attempt at a single explanation for the HIV epidemic in Asia or elsewhere. There is an undeniable need for further research through multicountry studies and better analysis of existing household data, as well as through further investigation of the quantitative relationship between the barriers to HIV services and the risk of infection. The key message for policy is to seek a broad balance between a focus on prevention and treatment for the higher-risk behaviours without losing sight of the importance of programmes that address vulnerability and behavioural change among the sexually active adult population. The implication of these findings for the allocation of resources for downstream factors such as risk behaviours as well as upstream development factors is briefly discussed.