There is little information regarding the extent of HIV infection amon
g women. Since late 1985, members of the Army Reserve Components have
been routinely tested for HIV, providing an opportunity to measure dir
ectly the prevalence and incidence density of infection in a military-
associated population with limited military contact. We evaluated the
prevalence among 122,195 women, and directly measured the incidence de
nsity among 96,001 women followed for 247,872 person-years. The overal
l prevalence was 0.65 (per 1000), and the incidence density was 0.12 (
per 1000 person years follow-up). Several demographically defined grou
ps, including minority women, had elevated levels of infection. The in
cidence densities of infection between early and late in the testing p
rogram were compared, and no evidence of acceleration or deceleration
was observed.