Hamilton Anxiety Rating Scale (HARS) is the most widely used semistructured assessment scale to evaluate the treatment outcome in anxiety disorders. Standardized interview guides were reported to minimize interrater variance. Joint-interview method with a structured interview guide (Hamilton Anxiety Rating Scale-Interview guide (Hamilton Anxiety Rating Scale-Interview Guide; HARS-IG) was used in a group of 20 patients to assess the interrater reliability of the scale. Criterion validity was also assessed by comparing the HARS scores with State-Trait Anxiety Inventory scores. The findings of this study demonstrate that HARS-IG is a reliable instrument and that it meets the standards of validity assessment.