Over the years, several interventions have been implemented, including Lego® Therapy, with the aim of supporting and implementing social and communication skills impairments in Autism Spectrum Disorders (ASD). Although recent studies have shown that the ability to learn implicitly is preserved in ASDs, no study related to Lego® Therapy has analyzed whether and how this training can also affect aspects not directly treated. In this study, we report a first attempt of assessment of Lego® Therapy's effect on the specific area of cognitive skills in an ASD child. Over a period of 12 months, a child with ASD had weekly meetings with an expert operator of Lego® aiming to improve the child's ability to communicate, reduce impulsiveness and hyper verbalism, and encourage pro-social behavior. The intervention resulted in positive outcomes that were assessed after 12 months.