Purpose. To identify worksite practices that show promise for promoting employee weight loss. Data Source. The following electronic databases were searched from January 1, 1966, through December 31, 2005: CARL Uncover (via Ingenta), CDP, CINAHL, Cochrane Central Register of Controlled Trials, Cochrane Library, CRISP, Dissertation Abstracts, EMBASE, ERIC, Health Canada, INFORM (part of ABI/INFORM Proquest), LocatorPlus, New York Academy of Medicine, Ovid MEDLINE, SPORTDiscus, PapersFirst, PsycINFO, PubMed, and TRIP.Study Inclusion and Exclusion Criteria. Included studies were published in English, conducted at a worksite, designed for adults (aged §18 years), and reported weight-related outcomes.Data Extraction. Data were extracted using an online abstraction form. Data Synthesis. Studies were evaluated on the basis of study design suitability quality of execution, sample size, and effect size. Changes in weight-related outcomes were used to assess effectiveness.Results. The following six promising practices were identified: enhanced access to opportunities for physical activity combined with health education, exercise prescriptions alone, multicomponent educational practices, weight loss competitions and incentives, behavioral practices with incentives, and behavioral practices without incentives.Conclusions. These practices will help employers and employees select programs that show promise for controlling and preventing obesity. (Am J Health Promot 2011;25[3]:e12-e26.)