The article is dedicated to legal argumentation research with regard to methodology of the general theory of law. General concept of argumentation is elucidated. In Ukrainian the term «argumentation» is used as a synonym of «reasoning» as well as «motivation». The second issue covered in the article is what makes the argumentation legal? With the purpose to answer this question properly it is necessary to stem from understanding of legal as determined by legal regularities. Mainly in legal researches the scholars avoid defining legal argumentation. Instead they propose theoretical model to test if something is legal argumentation or not. If defined by the scholar the term «legal argumentation» denotes the following concepts: 1) reasoning; 2) persuasion; 3) discourse; 4) dialogue; 5) trial; 6) the activity of putting the arguments (or theses and arguments). The correlation of legal argumentation with legal reasoning as well as proving and motivation depends on the context. In general legal context legal argumentation and proving are parts of legal reasoning. In the special legal context, namely judicial, reasoning of judgment is related to proving, whereas argumentation is related to motivation of court’s judgment.