Data were collected from an Early Intervention Foster Care (EIFC) group, a regular foster care group, and a community comparison group - each with 10 participants - via questionnaires for children and their caretakers and salivary cortisol sampling. EIFC foster parents adopted and maintained positive parenting strategies. EIFC children's behavioral adjustment improved, and changes occurred in several salivary cortisol measures. Moreover, regular foster care children exhibited decrements in functioning in several areas over the same time period. The article discusses study results with regard to how such research fits into a larger program of prevention research for high-risk preschool children. The larger program should include a randomized clinical trial involving a larger sample. Observed changes similar to those obtained in this smaller study might justify a larger-scale effectiveness trial, optimally demonstrating that the intervention's impact is not lost in the dissemination to community settings. Table, figures, references