The effects of an administration of the School Health Curriculum Project Heart Unit to a group of one-hundred and forty-five sixth-grade students of lower socioeconomic status was examined. The Heart Unit was administered over a period of nine weeks, five times per week, one hour per day. Participants were divided into separate treatment and control groups and the scores achieved by each on pre- and post-test administrations of the Teenage Self-Test on Smoking were analyzed. These analyses indicated that the only variables affecting performance on the cigarette smoking attitude inventory after exposure to the experimental curriculum were sex, residency status, best friend's smoking status, and older siblings' smoking status. Welfare status and parental smoking behavior did not appear to influence achievement on post-test mean scores. A significant difference was noted at the .05 level between pre- and post-tests of the students participating in the Heart Unit. Therefore, the curriculum appeared to have an effect on the experimental groups reflected in the significant difference between pre- and post-test mean scores. Based on these findings, it was concluded that: (1) the School Health Curriculum Project Heart Unit can be effectively implemented in lower socioeconomic schools; (2) females achieved significantly higher post-test mean scores than males; (3) welfare status does not influence post-test mean scores of those students exposed to the curriculum unit; (4) best friend's smoking behavior can influence a student's performance on the self-test on smoking; (5) older siblings at home who smoke can exert a negative influence on a student's performance on the self-test; and (6) parental smoking behavior does not exert an influence on student's performance with respect to the self-test. (MJB)