The ICD-10 Symptom Checklist is a semi-structured diagnostic instrument intended for clinicians' assessment of F0-F6 categories in the ICD-10 Classification of Mental and Behavioural Disorders. The instrument was preliminarily tested at the St. Louis site during its participation in the field trials of the ICD-10 Diagnostic Criteria for Research. The Checklist was found to be a reliable diagnostic tool (overall kappa 0.72) within the constraints of the interviewer/observer reliability study design. More rigorous tests of the psychometric properties of the instrument are necessary.