In this paper a revision of the epistemological principles, theoretical and methodological bases for a work on functional syntax is presented. For this purpose, a representative bibliography of the main functional schools is examined, mainly the North American functionalism as well as the European-Spanish one. It is also included an evaluation of three grammatical topics which are described from a functional perspective and illustrated through a pragmatic-grammatical methodology that takes into account the syntactic, semantic and informative level. The most important results show the necessity of continuing advancing in the design of methods of empirical analysis for linguistic phenomena pragmatically conditioned. At the same time, the methodology used must include linguistic and pragmatic descriptors with emphasis on the interaction between them.