The authors sought to verify teacher perceptions of prelinguistic behavior in eight children with autism. Teachers were first interviewed using the structured protocol of the Inventory of Potential Communicative Acts. The results indicated that the teachers interpreted many of the children's gestures, body movements, and facial expressions as if these were forms of communication. Naturalistic and structured observations were then undertaken to verify whether these teacher-identified behaviors did in fact seem to serve a communicative function. Observational data provided some evidence that teachers responded to such acts as forms of communication. This suggests that an interview protocol may be one way to document the form and communication function of existing prelinguistic behaviors in children with autism who are at the early stages of communication development.