According to the American Speech-Language-Hearing Association (ASHA), augmentative and alternative communication represents various modes of communication that can compensate for impaired patterns of communication in individuals with temporary or permanent limitations in expressive communication (ASHA, 2021). It is intended for people with complex communication needs with speech and / or language difficulties due to developmental disorders. It was once thought that children were not good candidates for implementing these interventions if they did not possess a certain level of cognitive ability (Wilkinson and Henning, 2007), and especially there has been limited implementation in younger children driven by a misconception about negative speech effects (Romski and Sevcik, 2005). Thanks to a growing body of empirical research on the effectiveness of assisted communication, ASHA rejects the previous view and comes to a new understanding of it as a continuum ranging from simple communication such as role change to more refined use of symbols (Wilkinson and Henning, 2007). There are also changes in potential candidates for the same, so these interventions are increasingly being implemented when working with children with developmental disorders in childhood. Today, the importance of implementing assisted communication in early intervention is emphasized given the great potential for incidental learning of young children as well as the importance of the child’s early experiences with the environment (Landa, 2018). Despite the significant benefits of assisted communication, the benefit of interventions in working with children with developmental disabilities is often underestimated, especially with associated intellectual disabilities. Clinicians and other professionals who work with children with developmental disabilities are obliged to implement in their clinical work those interventions for which there is scientific evidence of their effectiveness. Thanks to the hard work of experts in the field of assisted communication, they are considered scientifically based and as such are primary in early intervention. Despite their effectiveness, research speaks of variability in performance among children with complex communication needs. The aim of this thesis is to provide an overview of current knowledge on the possibility of implementing assisted communication in working with children with developmental disabilities at an early age (up to five years) with an emphasis on scientifically based interventions. These findings can serve as guidelines for professionals to work in clinical practice, but also as a basis for future research.