There is a great need to identify specific instructional methods that effectively promote positive skill development in young children with developmental disabilities. One method that has received strong empirical support with children with autism is Discrete Trial Teaching (DTT); however, the effectiveness of DTT has not been extensively evaluated with children who have developmental disabilities other than autism. This project was an initial investigation evaluating the practicality and effectiveness of providing DTT instruction to children with a wide range of developmental disabilities within an existing public preschool program. Participants were randomly assigned to receive DTT or individual attention in a control condition. The project evaluated the effects of providing DTT on the participants' cognitive, language, behavioral, and social-emotional functioning. Results generally indicated positive changes in adaptive behavior development and social-emotional functioning for students who received DTT. Implications and directions for future research are discussed. (Contains 6 tables.) [This research was partially supported by the Faculty Research Fund of Central Washington University, Ellensburg, Washington.]