This dissertation´s main objective is to investigate the possibilities of semantic variation on adverbials sentences introduced by the conjunction quando. We consider that, beyond the idea of time - to which some of our grammars use to be restricted - other adverbials circumstances, like cause and condition mainly, can coexist on the constructions formed by main clause and adverbial clause. To reach our goals, we based our study on the analysis of 70 examples found on O Globo journal and on Veja magazine., two of the most important vehicles of written communication in Portuguese. As a result, we concluded that, despite of the great importance of the role played by syntactical and grammatical factors, like the different combinations between verbal times and modes, the final meaning of the constructions that we examined is, definitely, determined by semantic factors, that is, the relationship of meanings established between the predicate and each of its terms.