Injecting drug use is being reported from an increasing number of Asian and other Third World countries. HIV continues to spread globally among and from populations of injecting drug users (IDUs), although the rate of spread appears to have slowed down recently in some industrialized countries. Asia produces two-thirds of the world's supply of opium. In recent years the rapid development of new illicit drug trade routes in efforts to evade detection by law enforcement authorities has exposed new populations in Asia to drug injecting and, thus, the risk of HIV infection. Epidemic spread of HIV has recently commenced in some Asian countries among injecting drug users, and others are at substantial risk of an HIV epidemic among their IDU populations. The speed of spread and the consequences of HIV infection among IDUs in Asian and other Third World countries are even more profound than in western countries. Asian countries attempting to control this component of the epidemic often have greater difficulty than industrialized countries because of their proximity to drug producing areas, scarcity of resources and a greater likelihood of pragmatic policies conflicting with traditional values. Vigorous efforts are urgently required at both a national and international level to raise awareness of the consequences of an uncontrolled epidemic of HIV among IDUs in Asian and other countries, and to support the implementation of policies which are likely to reduce the spread of HIV.