This study investigated the utility of self-report measures to screen for psychiatric comorbidities in autism spectrum disorders (ASDs). Thirty-eight 10-17 year olds with an ASD and without mental retardation completed: the "Children's Depression Inventory-Short version (CDI-S)", "Revised Children's Manifest Anxiety Scale (RCMAS)", "Conners-Wells Adolescent Self-report Scale-Short edition (CASS-S)", and "Short Leyton Obsessional Inventory-Child Version (SLOI-CV)". Their parents were interviewed with the "Autism Comorbidity Interview-Present and Lifetime (ACI-PL)" to establish psychiatric diagnoses. Sensitivity, specificity, positive and negative predictive values, and reliability coefficients were calculated for each self-report and compared to values from literature. The "CDI-S" and "CASS-S" yielded a high number of false negatives, with lower sensitivities and specificities in the sample than the literature. There was a nearly significant difference in total mean "RCMAS" scores between participants with and without anxiety, though again the means for both groups were below the threshold of concern. The "SLOI-CV" yielded a high false positive rate. All four instruments had reliability coefficients comparable to literature values. Results must be considered preliminary due to sample size. However, the findings suggest that although self-report instruments may provide useful information in the diagnosis of psychiatric comorbidities in ASD, caution must be exercised in their interpretation. (Contains 4 tables.)