The aim of the present study was to analyse family dinners as context of argumentation and argumentative development by using a context-sensitive model of basic argumentative structures in every day conversations. The data consisted of 40 argumentative sequences in dinner conversations in twenty Swedish families with children aged 7 to 17 years. The families were divided in two groups depending on the children's ages (10-11 years with younger siblings and 1012 years with older siblings). The model revealed characteristic structures of argumentation appearing as co-text and suggested differences between family groups depending on contextual factors such as age of the children. The groups of older children produced longer argumentative sequences, more exchanges per sequence and higher rate of turns. The older children also engaged in non-instrumental deliberations and disputations significantly more often and they performed more elaborated expansions (through a higher quantity of backing arguments). The groups of younger children on the other hand were more often involved in negotiations on topics relevant in the immediate context. Less expected was, however, the lack of more complex and varied arguments, even in the groups of older children.