Because blood specimens from newborns reflect the antibody status of the mother, seroprevalence rates among childbearing women are obtainable from analysis of the specimens. A blinded survey of human immunodeficiency virus (HIV) antibody seroprevalence among childbearing women was conducted in Maryland. The survey used 31,273 dried filter paper blood spot specimens obtained from newborns screened for hereditary disorders. Overall, 99 specimens were positive on two enzyme-linked immunoassays and on Western blot, providing a seroprevalence rate of 0.32 percent. The rate for child-bearing women residing within the City of Baltimore, 0.7 percent, was significantly higher than the rate for those residing elsewhere in Maryland, 0.1 percent. The statewide rate for nonwhite women, 0.8 percent, was higher than for white women, 0.007 percent. No statistically significant associations were found with residence in an inner city area, as opposed to residence in other areas of the city; birth weight group; reported health of the infant; or the infant having received a transfusion.