While designing effective intervention or treatment programs for at-risk populations is certainly of crucial importance, so is correctly and effectively implementing those programs in real-world settings. While data-driven program development has flourished, little attention has been focused on obstacles encountered by agencies when they attempt to implement these programs. As such, one of the main goals of the Blueprints for Violence Prevention initiative has been to encourage a more meaningful understanding of program implementation by examining the influences of human- and systems-level variables that present obstacles to the effective implementation of programs. The article describes the process evaluation of 42 sites implementing 8 Blueprints programs. Site visits were conducted three times a year for 2 years with each site. During site visits, questionnaires and formal interviews were conducted with staff members to assess the implementation process. Measures of implementation factors and success outcomes were derived from the literature. Results of univariate, bivariate, and regression analysis revealed that most of the 42 sites encountered many obstacles to efficient program implementation. The most salient factors challenging implementation were the quality of technical assistance available, ideal program characteristics, consistent staffing problems, and community support issues. These factors combined to influence one or more measures of implementation success. Future studies that focus on multiple program implementation in a variety of settings are needed to further stipulate the most and least crucial ingredients for the successful implementation of new programs. Tables, notes, references