The study examined the effects of condition and communication partner on spontaneous and elicited communication in children with Autism Spectrum Disorder (ASD) in comparison to age matched typically developing children. Eighteen children participated in the study (nine children diagnosed with ASD and nine typically developing children). Each participant was video recorded for 2 h 15 min periods across two conditions (academic activity and free-time). The two conditions represented a naturalistic view of the children's environment. Spontaneous and elicited communication were further analysed in terms of verbal behavior functions including requests, mands for information, mands for attention, greetings, terminating an activity, comments/tacts, language of negotiation, specifying using autoclitics and reject. Communication partner was further analysed at two levels, peer and adult. There was no difference between the frequency of functions of communication emitted and diagnosis of the participant. There was a significant difference for communication partner, whereby the main communicative partner for children with ASD was an adult in contrast to typically developing children who spoke more to their peers. Typically developing children engaged in more spontaneous communication than children diagnosed with ASD. (C) 2011 Elsevier Ltd. All rights reserved.