This study is about symbolic processes in atypical populations, which is presumed to lead to a deeper understanding of the ontogenesis of normal symbolic development. Exactly, we aimed to explore the emergence of symbolic play in children with Down syndrome (DS) and in children with autism spectrum disorder (ASD). A typically developing (TD) control group was also involved in the study. Fundamentally, we applied the qualitative method and focused on the replica play of the children that could be observed during their dyadic interaction with their parents. The activity of the individuals was recorded on video. The data were analysed with Noldus Observer XT 8.0 program software. The results confirmed atypical patterns of replica play in DS and ASD. Although both of these children groups demonstrated impairments in representational abilities, the autistic children seemed to have a basic cognitive defect. While children with DS were more often able to demonstrate coherent play activity, children with ASD could not use replica toys in the appropriate context verifying impairments in the social-communicative system. However, further studies are needed to cover the characterizations of psychopathological-specific disorders, to plan new diagnostic tools and more effective interventions.