Implementation research can facilitate drug prevention program efforts by elucidating factors that contribute to the dissemination of programs, expediting funding and resource allocations, enhancing the validity of summative evaluations derived from other measures, and contributing to changes in program theory and policy. Some implementation issues to consider include definitions of program adherence, exposure, and reinvention. Three types of measurement have been used to assess program implementation: self-report, other's report, and behavioral observation. Predictors of implementation include person, situational, and environmental influences. The author applies these implementation issues to school-based drug use prevention programs and recommends directions for future research. 1 table, 2 figures, 2 notes, and 42 references