The revision of the current classification criteria for disorders issued by the World Health Organization (WHO) (International Classification of Disorders, ICD-10) is underway and will also include a revision of the classification criteria of the mental and behavioural disorders. Working groups for specific groups of mental disorders had produced suggestions for revised diagnostic criteria and included a working group on schizophrenia and other primary psychotic disorders. This presentation will focus on this group of mental disorders. Major changes suggested were an introduction of symptom and course specifiers, the inclusion of cognitive symptoms and a de-emphasising of the so-called first rank symptoms of schizophrenia, a cross-sectional approach towards the classification of schizoaffective disorder and a reorganization of the acute psychotic disorders. Initial internet-based field trials showed some incremental improvements of diagnostic reliability, but more crucial for an adjustment of the revised classification criteria will be the expected results of the upcoming clinic-based field trials.