Background:The self-reporting questionnaire was originally developed by the WHO in order to screen for psychiatic disorders. To assess the validity of the Arabic self-reporting questionnaire (SRQ) as a screening instrument for psychiatric morbidity in a sample of Saudi medical patients. Methods: All patients referred for endoscopy underwent a semi-structured interview, and were then asked to fill out the SRQ. One hundred and sixty-six males and 126 females were included in the study. Results: Sixty percent of the subjects were identified by the SRQ as psychiatric cases, compared to 48.6% identified using the psychiatric interview. A cut-off point between six and seven, was found to yield a sensitivity of 93%, a specificity of 70%, and a misclassification rate of 19%. Females had more psychiatric morbidity than males. Conclusion:The validity indices and receiver operating characteristic (ROC) analysis support the usefulness of the SRQ as a cost-effective screening instrument for psychiatric morbidity in a two-stage large population research.