A study of 1,709 mother/child pairs at Boston City Hospital examined whether maternal cigarette smoking, drinking, or the use of other psychoactive substances was associated with low infant Apgar scores. The potential confounding effects of other labor and delivery risks were controlled in the analysis. In contrast to previous reports, univariate and stepwise multiple regression analyses did not identify a significant negative association between cigarette smoking and 1- or 5-minute Apgar scores. None of the substance use variables was significantly associated with low infant Apgar scores at 1 and 5 minutes. Other labor and delivery risks, such as short length of gestation, abnormal delivery presentation, placental abnormalities, nuchal cord, and exposure to general anesthesia during delivery, were associated with low Apgar scores.