Standardization of diagnosis is an essential preliminary in the clinical research in biological psychiatry. Between the different systems of nosographical selection, Research Diagnostic Criteria (RDC) are the most internationally diffused. After having recalled the spirit of RDC, we have looked for seven major illnesses (major and minor depressive disorders, endogenomorphic major depressive disorder, schizophrenia, manic disorder, panic disorder and generalized anxiety disorder) equivalents of RDC criteria in psychopathological and somatical items of AMDP system. With a minimum of modifications (adjonction of some reserve items for each illness), AMDP scales could become compatible. The verification of this theorical equivalence secondly makes it a duty to use jointly RDC and AMDP scales and to analyse both of them separately. After this methodological control, patients who meet RDC criteria could be automatically selected from AMDP scales.