The optimal utilization of the knowledge and possibilities of pathological and clinical biochemistry presumes a close cooperation between it and the clinical specialties. The common working team of the GDR Society of Internal Medicine and the GDR Society for Clinical Chemistry and Laboratory Diagnostics makes theses of the central points of the cooperation in care, education, further education and postgraduate study and in research a subject for discussion. As essential tasks in the process of medical care are regarded the balance of the examination programme standing at the disposal, the establishment of diagnostic programmes, the establishment of organisational measures, the ascertainment of a use according to indication, the guarantee of the representance of examination material, the control of plausibility and the interpretation of test results. Since the realization of the tasks to a large extent depends on the cooperation of the specialities in education, further education and postgraduate study during the further education the clinician should become acquainted with the possibilities, the limits and the prerequisites for the performance of laboratory diagnostic investigations, the clinical biochemist with the problems of medical care and the value of the laboratory diagnosis in the total process of the treatment. In the field of research the result is a necessary cooperation in the clarification of patho-biochemical mechanisms, in the search for suitable laboratory diagnostic parameters for diagnostics and control of the course as well as in the statement of the validity of laboratory diagnostic parameters and parameter combinations taking into consideration the factors expenses, benefit and risk as well as further diagnostic possibilities.