We consider the implementation, in a non-research setting, of a new prevention program that has previously been evaluated in a randomized trial. When the target population for the implementation is heterogeneous, the overall net benefits of the implementation may differ substantially from those reported in the economic evaluation of the randomized trial, and from those that would be realized if the program were implemented within a selected subgroup of the target population. This note illustrates a simple and practical approach to targeting that can combine risk-factor results from the literature with the overall cost-benefit results from the program's randomized trial to maximize the expected net benefit of implementing the program in a heterogeneous population.