The 10th revision of the International Classification of Diseases and Related Health Problems (ICD-10; World Health Organization, 1990) and the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) will both come into use in 1993 and be much more alike than the ICD-9 (World Health Organization, 1978) and the DSM-III (American Psychiatric Association, 1980). The American Psychiatric Association's controversial decision to publish a revision of the DSM-III in 1987 before setting up the Task Force to produce the DSM-IV impaired the association's ability to influence the format of the ICD-10, because by then major decisions had already been made by the World Health Organization. The DSM-IV will be more soundly based on a wider range of empirical data than any previous classification, national or international, and should not be revised again without compelling scientific reasons.