The article deals with the category of modality in the Spanish language and concentrates on modality of possibility. It aims at describing the semantics of possibility and gives the system for expressing different sub-meanings of possibility in Spanish. It analyzes how the modality of possibility is described within the framework of the functional-semantic approach which is realized in functional grammar. Three works by Gabriel García Márquez were a practise material to achieve the purpose of the paper. The model of the functional semantics of an utterance allowed getting basic formulae which reflect standard ways for communication of the modality of possibility in the utterance and standard situations behind them. The nucleus of the functional-semantic field of possibility in the Spanish language is "the internal inherent possibility". The examples which were selected by random sampling indicate that the system of expressing the modal meaning of possibility in the Spanish language has a strong verbal dominant.