Many children with autism spectrum disorders (ASD) have mealtime problems. Diagnosis and the social environment may influence eating behaviours. We examined whether children with ASD have more mealtime problems than their typically developing siblings, and whether age and sex are associated with mealtime problems. Forty-eight families participated in this cross sectional study by completing a questionnaire (Eating Profile) for their child with ASD, 3 to 12 years of age. A second Eating Profile was completed for the sibling nearest in age without ASD. Children with ASD had a mean of 13.3 eating problems, with lack of food variety predominating. Siblings had 5.0 problems. Children with ASD had more eating problems as infants. Older children tended to have fewer problems than younger children. This study points to the importance of screening for mealtime problems. Children with ASD had significantly more mealtime problems than their sibling living in the same social environment.