The authors used the Fagan Test of Infant Intelligence (J. F. Fagan, L. T. Singer, J. E. Montie, & P. A. Shepherd, 1986) to examine preferences for novelty and to evaluate several indicators of attention (off- and on-task indexes and durations) in 6- and 9-month-old infants who had been prenatally exposed to cigarette smoke only or to cocaine plus other substances. The infants were matched for socioeconomic status. The authors found no group differences in preference for novelty, but the off-task distractibility index and duration were affected by exposure history and showed effects of dosage at the 9-month test time. Infants exposed to cocaine had a higher off-task index and a shorter average off-task look duration than did infants in the other groups. The authors interpreted this pattern of behavior as an indicator of distractibility or stimulation seeking. There were no group differences in measures involving on-task looks or duration at either test time. Correlations between the off-task look index and duration and teratogen use produced moderate correlations at 9 months of age. The authors calculated partial correlations between teratogen exposure and the off-task index at each trimester. Cocaine use during the 1st and 2nd trimesters was significantly correlated with the off-task index at 9 months of age, even when the authors controlled for neonatal measures (e.g., gestational age, birth weight) and during the 1st trimester when they controlled for alcohol and cigarette exposure. (Contains 6 tables and 2 notes.)