A technique for generating good system decompositions is disclosed. The illustrative embodiment uses evolutionary programming in combination with a fitness function to generate a system decomposition that has a low degree of coupling and a high degree of coherence. A system is represented by an object-oriented specification using the Unified Modeling Language (UML); the UML specification is then represented by an eXtended Markup Language (XML) document, and the contents of the document are transformed into a nested-list data structure that resembles source code in a functional programming language such as Common LISP. The nested-list data structure and an appropriate fitness function are input to an evolutionary programming engine that operates on the nested-list data structure as though it were a source code program, and generates an output source code program. A system decomposition is then derived from the output source code program.