Refactoring aims to improve the quality of a software systems’ structure, which tends to degrade as the system evolves. While manually determining useful refactorings can be challenging, search-based techniques can automatically discover useful refactorings. Current search-based refactoring approaches require metrics to be combined in a complex fashion, and produce a single sequence of refactorings. In this paper we show how Pareto optimality can improve searchbased refactoring, making combining metrics easier, and presenting multiple sequences of optimal refactorings to users. General Terms Delphi theory Keywords Search-based, software engineering, refactoring, Pareto optimality