Children with autism spectrum disorders display atypical development of gesture production, and gesture impairment is one of the determining factors of autism spectrum disorder diagnosis. Despite the obvious importance of this issue for children with autism spectrum disorder, the literature on gestures in autism is scarce and contradictory. The purpose of this study was to analyze gestural communication in children with autism spectrum disorder during spontaneous mother-child interaction. Participants were children with autism spectrum disorder (n = 20), Down's syndrome (n = 20), and typical development (n = 20) and their mothers. Children's mean developmental age was 24.16 months (standard deviation = 1.45 months) and did not differ across the groups. Gestural communication was analyzed with a specific coding scheme allowing a quantitative and qualitative analysis of gestural production. Results showed the following: (a) differences between autism spectrum disorder, typical development, and Down's syndrome groups in the total number of gestures produced; (b) differences between the three groups in the distribution of gesture types; and (c) specific correlations between gestural production, cognitive development, and autism severity scores. The study of gestures in autism spectrum disorder could help us to identify different phenotypes in autism and could also lead to the development of new therapies.