Retrospective analysis of the epidemic of HIV infection in Moscow allowed to mark out two periods: the first--from 1987 to 1993 and the second one--from 1994 to 2000. The characteristic feature of the first period of the epidemic was the sexual transmission of the agent mainly among homosexuals; the most affected group were persons aged 20-39 years and the number of AIDS patient decreased with a simultaneous growth in lethality. During the second stage of the HIV infection epidemic changes in the prevailing transmission routes of the agent occurred: injection drug addicts took the leading role. Changes in the ratio of HIV-infected men and women took place along with active involvement of persons aged 13-18 years into the epidemic process. The established changes in the epidemiological situation require corrections in the strategy and tactics of epidemic control and prophylactic measures.