This paper describes the development of the recent HIV epidemic in countries of the former Soviet Union. It explores the socio-political and economic roots of an injection-drug-driven HIV epidemic associated with a drug culture that facilitates HIV transmission. This review, based on many unpublished reports, studies and field notes, discusses the new social and health context in which the epidemic is developing. The evidence of a growing number of drug users in the region is discussed and drug injection behaviour described. The authors present selected data on the heterosexual transmission of HIV and linkages between the drug-linked HIV epidemic and its further spread into the non-injecting population. The potential overlap with the still uncontrolled syphilis epidemic that began in 1990 is probably a key factor in the future of HIV spread in the region. Until now, HIV infection among STD patients has been extremely low. However, rapid changes in sexual norms and behaviours, the growing commercial sex industry, and increased mobility soon may affect the current situation. The huge economic and socio-political crises currently affecting the region have created a "risk situation" for the spread of HIV. Concerns are raised about the appropriateness and the scope of government and non-governmental approaches to the exploding HIV and STD epidemics.