With a polydiagnostic approach of schizophrenia in mind, the authors present, in french language, a computer-diagnostic instrument, essential for any research at the present time. This includes a 183-item checklist constructed from 14 diagnostic systems for schizophrenia and from Chronic Hallucinatory Psychosis (CHP), a typically french diagnostic entity, not recognized by English-speaking countries which do not individualize it from schizophrenia. This study tested the reliability in interviewing the patients simultaneously by 2 examiners with the checklist. The interrater agreement was excellent (Kappa from 0.75 to 1) for schizophrenic diagnoses under the systems CATEGO, DSM III-R, Feighner, ICD9, Langfeldt, Pull, Schneider and Taylor-Abrams. It was good (Kappa from 0.40 to 0.75) for the 6 other schizophrenic systems, Bleuler (k = 0.52; p > 0.01), Carpenter with a cut-off at 6 (k = 0.52; p < 0.05), ICD10 (k = 0.70; p < 0.01), New-Haven (k = 0.58), RDC (k = 0.59; p < 0.01), Vienne (k = 0.68; p < 0.01), and the Chronic Hallucinatory Psychosis (Pull) (k = 0.71; p < 0.01). The validity of the computer program was tested by the concordance (Cohen's Kappa) between the diagnoses established by a medical examiner and by computer, both obtained from the same collected data (the checklist). The tests show that the concordances were excellent for the 15 diagnoses for schizophrenia and CHP (Kappa form 0.75 to 1) and always above those obtained by the tests of interreliability.