EN
This article compares the usage of future forms of Spanish and Portuguese subjunctive mood. The usage of the future forms of Spanish subjunctive is analysed via diachronic and synchronic perspectives, which highlight the changes introduced in the Spanish modal system throughout the ages. The second part describes the usage of the future forms of the subjunctive mood in Portuguese. The conclusions comprise a short description of the modal, temporal and aspectual features of the Spanish and Portuguese subjunctive pointed out in the analysis proposed in the article.