Autism Spectrum Disorder (ASD) according to the Diagnostic and Statistical Manual for Mental Disorders (DSM-5, 2013) is defined as neurodevelopmental disorder characterized by the following diagnostic criteria: A) social communication and interaction deficits, B) atypical patterns of behavior, interests, and activities. The diagnosis of ASD is usually made when child is about 4 years old (Centers for Disease Control and Prevention, 2012). However, earlier recognition of ASD-related features is noticed and the importance of early intervention and its impact on the development of communication, language and speech is emphasized, where speech and language pathologist as a member of an interdisciplinary team plays an important role. The purpose of this paper is to present the effects of speech and language intervention in a two-year-old boy with ASD. One-year support is based on strategies for promoting communication and language, which have proved effective for encouraging children of very young age and include adapting the environment, following the guidance of the child, visual support, language modeling, using routine as a context for promoting communication and language and imitating the child. Techniques of augmentative and alternative communication with no aids (gestures, manual sings), low-tech aids (photos, pictures) and high-tech aids (tablets) are introduced in the work with the boy. The number and quality of communication functions and means were monitored according to the Pragmatic Communication Profile, and situational and language understanding was evaluated by croatian version of Communication Development Inventories (KORALJE). At the end of the intervention, the boy has demonstrated progress in the number of communicative functions and complexity of the means of communication as well as in situational and language comprehension. Moreover, in terms of promoting communication in the everyday life, the partnership with parents has been established.