Children with Autism Spectrum Disorders (ASD) display atypical development of gesture production, and impairments in gestural communication are among the most important features of ASD. Despite the obvious importance of this issue for children with ASD, the literature on gestures in autism is scarce and contradictory. The current study aimed at identifying specific characteristics of deictic gestures (i.e. pointing; showing; giving; requesting) in children with ASD during naturalistic mother-child interactions through the application of a detailed coding scheme. Participants were children with ASD (n=20), Down's syndrome (DS; n=20) and typical development (TD; n=20), and their mothers. Children's mean developmental age was 24.16 months (SD=1.45) and did not differ across the groups. Results showed differences between the three groups (a) in the total number of deictic gestures produced (b) in the distribution of several gesture types; (c) in the cross-modal complexity of gesture-gaze and gesture-speech integration. A comprehensive analysis of function, form, and complexity of gestural production is of specific relevance to the development and evaluation of novel treatments for addressing one of the core ASD symptoms, the capacity to interact socially in an effective way.