Résumé : This paper aims at proposing an original framework for the mapping of innovation systems. The analytical outline is based on the following paradigm: the innovation process has commonly been accepted as a complex system of interactions between different institutions aimed to achieve specific objectives through the efficient implementation of public instruments. More specifically, the objective of this paper consists, in a first step, in identifying and defining these innovation concepts. In a second step, the STI mapping is evaluated by crossing the STI objectives, instruments and institutional actors into four functional matrices that should all together empirically depict the innovation system. In order to strengthen the validity of the approach, an empirical example implemented at the EU-15 level is presented. The approach is based on the respect of the four following criteria: 1) international comparability of results; 2) representativeness of results; 3) measurement issues; and 4) consistency of the approach.