The 15 western European countries of the European Union accounted for an overwhelming 92.8 percent (149,403 out of 160,982) of all AIDS cases reported by December 1995, while in eastern Europe an epidemic of significance had not yet occurred (European Centre, 1996). More recently, the situation has changed dramatically. In December 1998, with more than 250,000 infections, UNAIDS and WHO estimated the number of persons living with HIV/AIDS in eastern Europe to have increased more than eightfold. There is strong evidence that the rapid spread of HIV in eastern Europe during the last 3 years has been mainly due to HIV transmission among injecting drug users. Uncertainties about the future course of the epidemic in eastern European countries remain, thus posing a serious dilemma for policymakers; programs and projects that aim to prevent HIV among intravenous drug users may not become effective sufficiently fast to prevent a substantial spread of HIV outside this group. Too little is known about sexual behavior and sexual networks in the successor states of the soviet Union. Rapidly spreading syphilis epidemics nevertheless highlight the potential for a further spread of HIV through sexual intercourse. There is thus a need for a policy that promotes HIV prevention among not only intravenous drug users, but also prostitutes. 4 figures and 135 references