In June 1982, the Direction of the French Hospitals introduced the project for the medicalisation of the system of information (PMSI) derived from the American Fetter system. The aim of this project was the collection of basic data necessary to the establishment of a national minimum data set base (MDS). Since 1985, a french regional cancer center, the Foundation Bergonié, has collected MDS by computer. Now, we give the results of the analysis concerning 28,379 MDS collected from 1986 to 1988. However, 11,127 (39%) MDS have not yet been analyzed by PMSI as they are connected with external activity or ambulatory care. It is possible to form a diagnosis related group (DRG) from the MDS to analyze the management of hospitals and utilization of means. 279 DRG were formed from 12,252 MDS, in our Institute. In fact, only 30 DRG with a sufficient number of MDS (over 100) were studied. This descriptive study shows that a few DRG maintain homogeneity in terms of length of hospitalisation especially in the surgical sector. It seems necessary to incorporate new criteria for MDS in order to improve the study of DRG; however groups sufficiently large for statistical analysis must be maintained.