Paris public hospital urology departments conducted a study which had three objectives: - to test the indicators of activity to determine whether they were well adapted to measurement of the surgical activity performed, - to determine the contribution of the PMSI to the measurement of this activity, - to propose actions designed to improve the representation of the surgical activity actually performed by urology departments. The results of this study show that one half of the operations performed do not correspond to the field of PMSI (day-only admissions, outpatients department). The indicators currently used for budget allocation or interdepartment comparisons of activity are inadequate and, most importantly, induce deformities, variable from one department to another, which severely affect the image of the activity produced by these indicators. Two main reasons can explain these deformities: - the use of the NGAP and the score to measure activity: there is a marked variation of the score for the same operation, from one department to another. - the very poor census of activity performed in outpatient surgery. These two reasons are not related to the medical activity. Definition of a unique nomenclature for surgical procedures would constitute a great progress, provided that this nomenclature allows us to accurately describe our activity and can be modified according to our needs. Although the PMSI is a marked improvement of the information system, its application, in its current state, will not radically change the situation. The PMSI must be enlarged in one way or another, to outpatient activity including procedures performed in the outpatients department. For these measuring tools of activity, which determine the calculation of our budgets, to be adapted to our practice, we must be able to analyse their relevance and introduce changes. We need to develop this field of medico-economic research in urology.