The purpose of this study was to compare the effects of a speech generating device with a dynamic display and a picture board on the communicative functions of children with autism spectrum disorders (ASD) as the children participated in theme based play activities. Two preschoolers with autism spectrum disorder who were minimally verbal participated in this study. This study used an alternating treatment design in which the communication systems were alternated between sessions. Each participant participated in five sessions. The first session was without either treatment option followed by four treatments sessions in which the speech generating device and picture board were alternated by session. Each child participated in two sessions with the speech generating device and two with the picture board. Fourteen theme based vocabulary words were chosen to target for each session. Seven of these were constant and seven changed each session. The icons were the same on the SGD and picture board. The results of this study were inconclusive. Neither condition affected communicative functions used by the participants. However, both participants did learn, with a limited amount of teaching, to use both devices. One participant communicated more frequently with the picture board and one with the SGD.