The objective of our study is to estimate the prevalence of comorbid psychiatric disorders in a sample of children with autism spectrum disorders (ASD) recruited from three Arab countries. We also examine the relationship between comorbidity and children's cognitive functioning and gender. Children who received a diagnosis of ASD (n = 60) from a child psychiatric outpatient clinic in Mansoura (Egypt), Al-Ahsa (Saudi Arabia) and Amman (Jordan) were included in this study. Comorbid diagnoses were established with a clinical interview and a semi-structured clinical interview for children and adolescents (SCICA). In addition, for all patients the cognitive evaluation was measured given the range in age and level of ability. Sixty-three percent of the children were diagnosed with at least one comorbid disorder. The most commonly reported comorbid disorders were anxiety disorders (58.3%), ADHD (31.6%), conduct disorders (23.3%), and major depressive disorder (13.3%). Out of the total sample, Obsessive compulsive disorder was the most prevalent anxiety disorder (55%). Elimination disorders were also diagnosed in 40% of patients. These findings emphasize a wide variety of psychiatric comorbidity afflicting youth with ASD and may be important targets for intervention. (Contains 2 tables.)