Despite considerable speculation on the demographic impact of AIDS, th
ere has been, until now, little scientific evidence to establish its e
xistence or scale. Because of the widespread implications of these pre
dictions, methods to combine demography and epidemiology to study empi
rical situations have been an urgent priority. This study derives the
extent and mechanisms of demographic impacts of AIDS from routine data
(the 1991 census) in a severely affected country, Uganda. Three chara
cteristics are of particular note: first, the emergence of demographic
impacts much earlier than previously estimated; second, their localiz
ation with negative population growth at parish but not at district or
national scales; third, a greater impact on the number of children th
an previously predicted(1,2), due as much to changes in population fer
tility as mortality. The emergence of demographic impacts at this stag
e highlights original aspects of the interdependence of HIV infection
and demographic growth not previously recorded and the need to target
preventive interventions to youth in developing countries.