This paper gives a brief outline of the present state of development of the psychiatric chapter of the tenth revision of the International Classification of Diseases (ICD-10). It is written from the point of view of one of the many consultants to the Division of Mental Health, World Health Organization (WHO), Geneva, and thus is not an authoritative or official statement on behalf of WHO. The responsibility for decisions about ICD-10 Chapter V (F) rests with Dr Norman Sartorius, Director of the Division of Mental Health, though many psychiatrists in many countries have contributed to ICD-10 Chapter V (F), and will continue to do so, since much work is still to be done before the final form is officially agreed and published in about 1990. Before he left WHO, Geneva in September, 1986, Dr Assen Jablensky also carried a great deal of responsibility for the arrangements necessary for the production of the drafts of ICD-10 Chapter V (F) that are now being developed.