PIP: Papers presented at the Ninth International Conference on AIDS and STDs in Africa, held in Kampala in December 1995, indicate that HIV prevalence has been declining in several sectors of the population in Uganda over the past few years. This paper reviews the following relevant presentations: studies among pregnant women in Mulago hospital, Kampala; sentinel surveillance data; a community-based study of HIV in Masaka district; a community-based study in Rakai district; and persons attending voluntary HIV testing in towns in Uganda. Most of the data presented come from urban areas. Approximately 90% of the country's population, however, lives in rural areas. All of the studies document declining trends in HIV prevalence in the populations studied. The author considers whether these findings represent what is happening in the general population and what is behind this trend. On the basis of the presentations made during the conference, it seems that the main factors affecting current HIV seroprevalence trends in Uganda are HIV incidence, HIV-related mortality, and demographic changes. The role of each of these factors is discussed in light of the available evidence. More specifically, there appears to be a real decline in HIV seroprevalence in some population groups in Uganda. Very high HIV-related mortality, the movement of many young people into the adult demographic category while retaining their HIV-negative status, and probably a lower HIV incidence rate than that prevailing before 1990 are some of the explanations for the observed trend.