Autism is a pervasive developmental disorder characterized by deficits in the areas of communication, socialization and behavior. Current diagnostic criteria have been modified in a restrictive sense, thus the possibility that individuals with milder impairments may not reach the diagnostic threshold is concrete. Furthermore, heterogeneity in phenotypic expression and the high rate of comorbidity with other psychiatric disorders would make even more difficult the diagnostic classification in individuals with autism spectrum disorder (ASD). The present study was a Rorschach investigation aimed to identify specific psychopathological elements to properly orient the diagnosis of ASD in adulthood. Results have shown that the examined subjects were characterized by pragmatism, documented by the presence of details and little details, falls in formal thinking, thought inflexibility, lack of answers with human content, and the prevalence of particular phenomena (denial, perseveration). Data obtained in the study showed a specific pattern of psychopathological signs in adults with ASD, thus suggesting the importance of projective methods for a better understanding of the clinical features of avoidance behaviors and relationships.