The effectiveness of a smoking-prevention program—incorporated within a traditional science curriculum—was assessed in terms of attitude modification in such categories as health, peer pressure, and social image as related to smoking. The study indicates that most relevant attitudes, the emotionally intense in particular, are modifiable in the desired direction, although the changes are small. Some gender differences in the recorded changes suggest a difference in the dynamics of the response to smoking intervention between male and female high school students. A desired change of attitude frequency distributions (e.g., from less extreme to more extreme responses) has also been found. In addition, the tendency of the experimental students to actively act against smoking within family circles increased, although not significantly. All the above was accompanied by a decrease in the number of smokers in the experimental group and a significant increase in the number of smokers in the control group. These results suggest that it is educationally possible to modify attitudes in health education in the desired direction by means of a properly designed interdisciplinary science curricular unit implemented within ongoing traditional science teaching.