During a multicentric field trial involving 134 diagnosticans from 16 centres in a first phase and 38 diagnosticans from 5 centres in a second phase a preliminary version of the manual "Operational Psychodynamic Diagnosis (OPD)" was tested. Focussing on feasibility, practicability and interrater-reliability the different axes of the new system were assessed as comparatively easy to use. The goodness of fit for diagnostic categories and the confidence in the diagnostic process showed a sufficient acceptance of the system. The percentage and chance-corrected inter-rater-reliability coefficients were acceptable for the most axes. It could be demonstrated that interrater-reliability depends on the degree of experiences with the OPD approach. Therefore a systematic training is necessary to use the system.