This report examines the unique factors or circumstances pertaining to HIV and migration in select countries of South and North East Asia that need to be taken into account while planning a response to the epidemic. It highlights an increasing level of mobility in all the seven countries, both within and across national borders. Although some of this mobility is 'formal', much of it is informal or 'irregular'. Further, the findings reinforce the fact that the type of population mobility and the context and conditions in which it occurs - whether under duress or distress, or in unprepared conditions - affects the vulnerability of migrants and their families to HIV.