The aim of this study is to assess the reliability and validity of a Persian translation of the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders (SCID-I) through a multicenter study in a clinical population in Iran. The sample consisted of 299 subjects admitted to outpatient or inpatient services of 3 psychiatric centers in Tehran, Iran. The SCID was administered by trained interviewers. To study the test-retest reliability, a second independent SCID interview was administered to 104 of the entire sample within 3 to 7 days of the first interviews. For the assessment of validity, the SCID diagnoses were compared with the consensus clinical diagnoses made by 2 psychiatrists for all 299 patients. Diagnostic agreements between test and retest SCID administration were fair to good for most diagnostic categories. Overall weighted kappa was 0.52 for current diagnoses and 0.55 for lifetime diagnoses. Specificity values for most psychiatric disorders were high (>0.85); the sensitivity values were somewhat lower. The Persian translation of the SCID yields diagnoses with acceptable to good reliability and validity in a clinical population in Iran. This supports the cross-cultural use of the instrument.