Objective data about the costs of nuclear medicine examinations are scarce and rather conflicting. Authors describe a method quantitating the costs of nuclear medicine investigations. These calculations were applied to a medium-sized nuclear medicine center set up in a teaching hospital. Calculations were as a tarification and followed the rules of monographic studies. They rely on exhaustive evaluation of each expense and precise analysis of their repartition. Average cost of the examination was 1,016 FF but the study reveals that costs varied from 664 to 6,746 FF. It appears that, but the more common investigations, exact costs are poorly related with nomenclature codification and that radiopharmaceutical costs have to be separately dealt with. This method allows to simulate costs-effects of any structure modification before being applied. One of the major feature of such a study is that it depicts a given center at a given time. Although it is to be hoped that the method should be spread, it should be hazardous to generalize its results.