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In this paper we introduce Definite Clause Translation Grammars, a new class of logic grammars which generalizes Definite Clause Grammars and which may be thought of as a logical implementation of Attribute Grammars. Definite Clause Translation Grammars permit the specification of the syntax and semantics of a language: the syntax is specified as in Definite Clause Grammars; but the semantics is specified by one or more semantic rules in the form of Horn clauses attached to each node of the parse tree (automatically created during syntactic analysis), and which control traversal(s) of the parse tree and computation of attributes of each node. The semantic rules attached to a node constitute therefore, a local data base for that node. The separation of syntactic and semantic rules is intended to promote modularity, simplicity and clarity of definition, and ease of modification as compared to Definite Clause Grammars, Metamorphosis Grammars, and Restriction Grammars.