Results indicated that the two different curricula under examination were implemented as intended. Students had positive perceptions of the curricula and showed significant improvements in knowledge specific to the curricula delivered by Project TND. The findings suggest that the differences in student outcomes can be attributed to the content of material provided in the two curricula conditions rather than to differences in the fidelity of program delivery. The results also suggest that Project TND may be implemented effectively with both low and high risk youth in a variety of settings. The implementation fidelity evaluation focused on two theoretical content components of the curriculum. Eighteen senior high schools were randomly assigned to receive 1 of 3 conditions: cognitive perception information curriculum, cognitive perception information + behavioral skills curriculum, or standard care (control). These curricula were delivered to 2,331 high school students by trained project health educators and regular classroom teachers. Data analysis was completed in the SAS statistical package using a generalized mixed-linear model. Future research designed to assess the effectiveness of drug prevention programming should first evaluate the fidelity of implementation. Tables, references