PurposeThe assessment of Autism Spectrum Disorders (ASD) in childhood has two essential aspects: the identification of the risk (under 30 months of age) and the definition of a diagnosis that takes into account its core areas as well as further non-specific aspects. The purpose of this paper is to present an approach that considers the combination of clinical evaluation with the use of tools that analyse the various levels of the child’s functioning as fundamental.Design/methodology/approachThe comprehensive assessment at the Institute of Ortofonologia in Rome provides the ADOS-2 and the Leiter-R for the evaluation of the symptomatology, the severity level, the non-verbal cognitive functioning and the fluid reasoning; the TCE and the UOI are used to identify, respectively, the child’s emotional skills and the ability to understand the intentions of others, as precursors of the theory of mind. Within this assessment, the Brief-P, the Short Sensory Profile and the RBS are also included for the evaluation of executive functions, sensory pattern and of restricted and repetitive behaviours, as observed by parents.FindingsHow to define a reliable development profile, which allows to plan a specific intervention calibrated on the potential of the child and on his development trajectory, is described. Two clinical cases are also presented.Originality/valueThe entire process is aimed both at a detailed assessment of the child’s functioning and at identifying a specific therapeutic project and predictive factors for achieving an optimal outcome.