Given the significant rates and deleterious consequences of childhood sexual abuse (CSA), identifying effective primary prevention approaches is a clear priority. There is a growing awareness that childcare professionals (e.g., teachers, childcare personnel, clergy) are in a unique position to engage in prevention efforts due to high accessibility to children and expertise in child development. However, CSA prevention programs targeting childcare professionals have received insufficient attention. The goal of this study was to conduct an independent multi-site controlled evaluation of an existing CSA prevention program, Stewards of Children, offered through both in-person and web-based formats. This study included 352 childcare professionals recruited from children's advocacy centers across three states. Participants were randomly assigned to one of three conditions: (1) in-person training, (2) web-based training, or (3) waitlist control. Dependent variables included CSA knowledge, CSA attitudes, and self-reported CSA preventive behaviors. Results indicated that Stewards impacted knowledge, attitudes, and preventive behaviors. No differences were found between training modalities (i.e., in-person versus web-based) on knowledge and preventive behaviors. Results indicate that brief trainings for childcare professionals may impact CSA prevention efforts. (author abstract)