The paper analyzes the negotiator’s position reasoning techniques and their relations in terms of sustainability. In negotiations takes part at least two sides trying to achieve a common purpose and understanding. Each negotiator has to base on their position in one way or another and to convince the opponent. Although the forms and channels of communication in this century is improving very rapidly, but the immediate value of real business meetings and negotiations remains very important. The most important and critical negotiating agreements are still going on and meetings face to face will go for a long time. Chat is one of the best and most acceptable ways to convince someone in validity of his position, that he would agree with the opponent‘s position and will adopt it or maintain. For reasoning the negotiator’s position are used following techniques: evidence, reasoning, counter reasoning, manipulation, persuasion, suggestion. This paper gives an overview of these techniques, their fundamental characteristics, features and logical relations from the view point of sustainability.