Brazilian Portuguese (BP) permits at least three kinds of sentential negation – Neg1 (não VP), Neg2 (não VP não) and Neg3 (VP não). The topic of this paper are the different interpretations of Neg2 and Neg3 in comparison to Neg1. I argue that Neg2 is a Negative Concord element that exhibits properties associated with presupposed denial, while Neg3 is interpreted as a kind of focus operator. Some contexts show the incompatibility between Neg2/Neg3 and Neg1. I believe that this incompatibility can be explained by presuppositional content and scope. The aim of this paper is to explain the relation between negation structures in BP and pragmatics.