This study examined the factor structure of the Brazilian version of the Autism-Spectrum Quotient. This is a self-report questionnaire for continuous and quantitative assessment of autistic spectrum traits in adults. Confirmatory factor analysis was performed on the five-factor model (social skill, attention switching, attention to detail, communication and imagination) proposed by the original authors, support not being found for this model in our sample. An exploratory factor analysis was then performed that resulted in an alternative three-factor model (social skills, details/patterns and imagination). Confirmatory factor analysis of the latter model revealed adequate psychometric indexes. The Brazilian version of the AQ was shown to be an adequate instrument for the evaluation of signs compatible with the autism spectrum in adults.