Parents of children with autism spectrum disorder are known to experience more stress than parents of children with any other conditions. The current study describes the parental stress of 118 fathers and 118 mothers at the onset of their children's Early Intensive Behavioral Intervention program. The objectives of the study were to compare and analyze each parent's stress and to identify factors that might predict their stress. Results indicated that fathers reported higher levels of stress than mothers. Correlations indicated that the stress levels of both parents were associated with their child's age, intellectual quotient, severity of autistic symptoms, and adaptive behaviors. Paternal stress, but not maternal stress, was predicted by severity of autistic symptoms and child's gender. Results are discussed in terms of their implications for services and early interventions.