Taking into consideration the central role played by argumentation in children's culture, comparative studies regarding the relative contribution of peer talk and children-teacher talk to children's argumentative discourse at kindergarten are relatively scarce. In this study, the researchers gathered ethnographic data of natural peer interactions and small-group discussions with the teacher to identify characteristic features and analyze the argumentative events along different aspects: discursive, interactional, and textual. (Contains 4 tables and 11 notes.)