This chapter considers the question of whether an arbitrator may also adopt a mediation function or whether the dual roles are antithetical. It tests that hypothesis by engaging in a cost-benefit analysis of differing scenarios when mediation is utilized in an arbitral context. The prime comparison is between parallel mediation with a separate neutral and the alternative of a dual-role neutral. The three key points are: there should be much more mediation occurring at the international level, regarding both potential and actual arbitral disputes; a commercially minded arbitrator concerned for the parties’ good faith should encourage mediation where appropriate, in particular, when an adjudicated outcome will not be in the interests of either, usually because the dispute is a small part of a long-term relationship that can risk that relationship no matter who wins; and, while informed party autonomy should always support a dual-role neutral, in most factual permutations, informed parties could be expected to prefer parallel mediation provided there is full cooperation between mediator and arbitrator. The chapter argues that the relative benefits of the use of dual-role neutrals would be greatly outweighed by the costs in fairness and efficiency, and the inevitable need for a sub-optimal design of either or both dispute processes. The benefits would also be separately outweighed by the risks of significant disruption to any ensuing arbitration if a dual-role neutral fails to achieve a settlement.