PIP: By January 1992, almost 450,000 AIDS cases had been reported to the Global Program on AIDS of the World Health Organization (GPA/WHO), but the estimated number of adult cases was 1.5 million based on about 1000 available HIV serological survey data and HIV data bases. 2 million people in the Americas, 1/2 million in Western Europe, over 6.5 million in Sub=Saharan Africa, and 1 million in South and Southeast Asia have been infected since the pandemic started. In North America and Western Europe, the incidence has been declining since the mid-1980s (50,000 cases/year in the US, several times more in the early 1980s). During 1991 in sub=Saharan Africa, 200,000 adult AIDS cases occurred in accordance with the 10-years latency of the disease. The estimated figures of HIV infection as of early 1992 were 5-7 million men and 3-5 million women with 1.5 million full-blown AIDS cases, 90% of whom have died. In sub-Saharan Africa, 1 out of 3 children born to infected mothers become infected, and almost 1 million infected children have been born in the world since the pandemic started. The peak incidence of AIDS cases is expected in the mid-1990s in developed countries because of high HIV infection rate in the early 1980s. A steady increase of heterosexual transmission is projected depending on the effectiveness of HIV/AIDS prevention programs. In developing countries, AIDS cases and attendant mortality are expected to increase substantially in the 1990s and beyond with AIDS becoming the leading cause of death among adults in productive life. In sub-Saharan African cities, HIV seropositivity may range from under 10% to 30% in the 15-49 age group. The improvement of surveillance and estimation methods of HIV/AIDS prevalence is a prerequisite of AIDS programs of health care systems.