In the last years there has been an increasing demand of a variety of logical systems, prompted mostly by applications of logic in AI, logic programming and other related areas. Labelled Deductive Systems (LDS) (Gabbay, 1996) were developed as a flexible methodology to formalize such a kind of complex logical systems.
In the last decade, defeasible argumentation (Simari 1992, Prakken-Vreeswijk 1998, Verheij 1996, Bondarenko et. al 1997) has proven to be a confluence point for many approaches to formalizing commonsense reasoning. Different formalisms have been developed, many of them sharing common features. This paper presents an argumentative LDS, in which the main issues concerning defeasible argumentation are captured within a unified logical framework. The proposed framework is defined in two stages. First, defeasible inference will be formalized by characterizing a defeasible LDS. That system will be then extended in order to obtain an argumentative LDS. We will present an example to characterize different features in our formalization.