One hundred and ten, 6- to 11-year-old children from a low-risk, predominantly middle class sample who are participants in an ongoing longitudinal drug study were assessed using a central auditory processing task (SCAN) that made perceptual rather than linguistic demands. Maternal smoking during pregnancy was linearly associated with poorer performance on the overall SCAN and, particularly, the Competing Words subtest which may be an indication of the child's auditory maturation. The significant associations remained after adjusting for other drug use, demographic variables, and passive smoke exposure both during pregnancy and postnatally. The child's recent second-hand smoke exposure was evaluated by a parental questionnaire and by urine cotinine assay. Neither prenatal nor postnatal passive smoke exposure was statistically significantly associated with the SCAN results. However, among the children of nonsmokers, passive smoke exposure resulted in average scores similar to those of the prenatal light smoking group. The findings are discussed in relation to earlier observations that have reported an association between smoking during pregnancy and altered auditory functioning in the offspring.