Objectives: To explore the relationship between causal beliefs on autism (CBA) and treatment choices. Design and methods: A cross-sectional design was employed. Parents of a child with autism spectrum disorder (ASD) were asked to complete the Lay-Beliefs about Autism Questionnaire (LBA-Q) and answer questions about treatments used. Only items inquiring about a cause of autism were retained for analysis. Series of forward stepwise logistic regressions were performed with each treatment as dependent variable and the scores given to each of the CBA items as independent variables. Results: 78 parents were included. The most strongly held causal beliefs were brain abnormalities and genetic factors. Parents who had more beliefs in the causal role of very early traumatic experiences were less likely to use behavior therapy and PECS. Higher beliefs in illness during pregnancy increased the odds of medication use. Stronger beliefs on the role of food allergy were associated with higher use of detoxification treatments, special diets, and vitamins. On the contrary, these beliefs reduced the odds of drug use. Conclusions: Causal beliefs are associated with treatment choices. Such preliminary results highlight the value of continued studies, not only to establish the causal nature of these associations, but also to demonstrate the utility of modifying such beliefs for both parents' and child's benefits. Identifying parents' beliefs about their child's illness may be an important step in formulating interventions facilitating appropriate care.