Although children and adolescents with developmental disabilities are said to have higher risks of abuse than those without, trauma and Posttraumatic Stress Disorder (PTSD) are little examined in those diagnosed with Autistic Spectrum Disorders (ASDs). Our study aims to assess trauma types, prevalence, risk factors and symptoms; and PTSD in individuals with diagnosis of ASD. Participants were 69 children and adolescents (53 males, 16 females) who were consecutively followed-up at our clinic and met DSM-IV criteria for ASD. Assessment was done using semi-structured interview forms. 18 had trauma history and 12 were diagnosed with PTSD. Witnessing or being a victim of accidents/disasters/violence was the most common type of trauma. Interestingly, the rate of sexual and/or physical abuse was less than in the general population. Trauma history and PTSD rates were higher in girls than boys. Deterioration in social and communicative abilities, increase in stereotypes, aggression, distractibility, sleep disorders, agitation, hyperactivity, self-injury, and loss of self-care skills were the most common symptoms detected following trauma. These results underscore the importance of detailed assessment of behavioral and emotional problems in this group by ruling out any trauma history at periods which might otherwise be misdiagnosed as an exacerbation of symptoms of ASD. (Contains 3 tables.)