This study is part of the ICD-10 field trials in which the use of case vignettes for interrater agreement has been examined. From our electronic database of 880 consecutively admitted inpatients we selected 24 cases that were transcribed to vignettes covering the first 5 ICD-10 target syndrome of dementia, substance use disorders, schizophrenia, mood and anxiety disorders. ICD-10 was compared with ICD-8 and DSM-III. The results showed that all 3 standard classification systems obtained an acceptable interrater agreement. Among the diagnoses, depressive disorders gave rise to most disagreement between the raters. Discrepancies between the methods of measuring interrater agreement were found when intraclass reliability was compared with consensus calculations for the individual patient.