Abstract. Action description languages, such as A and B (Gelfond and Lifs- chitz, 1998), are expressive tools introduced for formalizing planning domains and problems. In this work, we investigate two alternative approaches to the prob- lem of encoding action languages using logic programming. Starting from a slight variation of B, we explore the use of Answer Set Programming (ASP) and Con- straint Logic Programming over Finite Domains (CLP(FD)) in processing action theory specifications. As regards ASP we present a Prolog translator from action theory into lparse’s syntax. Concerning CLP(FD), we describe a program that directly processes a specification in the B language.