The chapter by Rose draws a sketch of negation in Mojeño Trinitario, an underdescribed South Arawak language spoken in Amazonian Bolivia, and discusses its interaction with irrealis. It starts with presenting the different negation markers and constructions used for each negation type: sentential negation (including the expression of apprehensive, and negation in subordinate clauses), free form answer, constituent negation, existential negation, negative indefinites and privative derivation. The paper then discusses the most interesting point in the expression of negation in Mojeño Trinitario, i.e. its interaction with irrealis. First, irrealis marking is obligatory both in sentential negation and in existential negation. Second, standard negation induces a realis/irrealis coding that is distinct from that occurring in affirmative clauses. This paper argues that standard negation is of the constructional asymmetric type: a negative clause is asymmetric with a corresponding positive clause, on the basis of obligatory irrealis marking and the placement of some TAM and discourse markers on the negative word. In the end, it points to how the encoding of the irrealis may be complex in the languages where the irrealis category covers a wide range of meanings including negation, since irrealis encoding is then redundant with negation encoding.