This paper outlines the combined use of the PMSI information system and geographical data for regional planning of hematology department activities in the Nord-Pas-de-Calais Region (France). The PMSI information system is comparable to the DRG approach used in other countries. Data extracted from hospitals PMSIs are transferred to specific databases where quantitative geographical methods are applied. Thus, potential information becomes available, in particular in the context of the evolution of the Healthier Regional Policy. The study also provides evidence that the PMSI pertains interesting regional information about morbidity of specific kinds of diseases