This paper presents a formal method how to transform the structured signature of an algebraic specification into a collection of object-oriented class signatures. We discuss possible design decisions and formalize them as design mappings. The transformation of the signature forms the syntactic basis for relating algebraic specifications with object-oriented modeling in a profound way. The approach bridges the gap between functional specification concepts and objectoriented modeling techniques and contributes to a better understanding of object-oriented software construction. We illustrate the transformation with a characteristic example. All transformation procedures have been implemented in the ASIOS tool.