The aim of this work is to investigate the issue of discourse negation observed in ne … -sI structures in Turkish casual conversations. We show that discourse negation observed in the structures under discussion involves strong objection to the original statement and a subsequent rectification of it. The strength of the utterance provided by the special linguistic forms and intonation in these structures is the main tool which differentiates them from other regular instances of negation in Turkish. We provide three sets of discussions for the issue: (i) argumentative discourse mode, (ii) tri-partite discourse structure, and (iii) descriptive vs. metalinguistic negation. With respect to (i), the paper claims that the structures under discussion involve an argumentative discourse mode where Speaker B asserts a strong objection to, denial and refusal of the statement made by Speaker A as the first part of his/her answer. The consequent strong rectification in the second part of the answer by Speaker B is another support for the argumentative mode. For (ii), we show that a tri-partite discourse structure is observed where the first part involves an expectation statement by Speaker A, the second part includes Speaker B’s strong objection to this expectation, and the third part includes Speaker B’s strong rectification of the denied information. With respect to (iii), the paper shows that the structures under investigation have a dual nature with respect to descriptive vs. metalinguistic negation. We present some cases of descriptive negation with a strong objection as opposed to others that may include metalinguistic negation with weak or “fake” denials.