The HIV seroprevalence per 100,000 adults Malagasy rose from 20 in 1989, to 30 in 1992, and to 70 in 1995. In that year, the total number of HIV infected people in the Big Island was estimated at 5,000, the number of people sick with AIDS at 130, and the people at risk at more than 1,000,000. The latter are the persons infected with other STDs and individuals (or their partners) with risky sexual behaviour (e.g. numerous sexual partners, occasional sexual partners, and/or sexual contacts with commercial sex workers). The HIV prevalence rate is low as compared with those of other countries. Nevertheless, the spread of the HIV infection is alarming in some parts of the country and the risk factors are also present, namely: the high prevalence of STDs, numerous sexual partners, the low use of condoms in all groups, the development of tourism, the development of prostitution associated with social and economical problems, and internal and international migrations (with risky sexual contacts). Therefore, the still low but rising HIV prevalence in 1995 does not warrant complacency. To estimate the trend of HIV prevalence within the population, it is useful to know two different assumptions, as follows: firstly, a controlled evolution of the epidemic (low epidemic) and secondly, a very fast spread of the epidemic (high epidemic). If we consider the 5,000 individuals seropositive in July 1995, the Aids Impact Model (AIM) projection model shows that HIV seroprevalence rates among adults in 2015 might be between 3% (when the progression course of HIV epidemic is low) and 15% (when the progression course of HIV epidemic is high). By 2015 AIDS could have severe demographic, social, and economic impacts. Then, it is necessary to take measures to prevent contamination. Five major interventions are required: public information about AIDS, HIV transmission mechanism, and its prevention, communities education via the respected people and the notabilities to promote moral values, reduce the number of sexual partners, delay visit of sexual activity, and advice for infected couples; screening of blood donors and the supposed high risk group; control of STDs; reduction of the number of sexual partners; promotion of condom use, abstinence, and fidelity. To sum up, the fight against AIDS is not only the health professional workers' problem. It concerns all Malagasy people. Therefore, successfullness in prevention efforts to slow the epidemic needs concerted, collective, and long lasting actions from all sectors of the society for the nation's future and the well-being of the rising generations.