Many lawyers are now involved in mediation, either as a mediator or as a legal representative for one of the parties to the mediation. These roles raise a host of new ethical dilemmas for lawyers. The focus of the literature to date concerns the ethical complexities faced by mediators. Comparatively little attention has been given to the ethical position of legal representatives. This paper identifies some common ethical issues which arise in mediation from the perspective of legal representatives for the parties. It focuses on the issue of disclosure of information (an issue which itself raises questions about honesty as against misrepresentation and openness or candour as against non-disclosure) and suggests how the issue might be resolved using the current rules of professional conduct governing lawyers in two common law jurisdictions, those of Australia and the USA. Each jurisdiction has taken a different approach on the issue. In the USA, legal representatives owe mediators the same duties of disclosure as they owe to their opponents. In Australia, it seems that legal representatives may owe mediators the same duties as they owe to judges in a court of law. This paper will argue that the approach taken in the USA (based on the much-criticised rule 4.1 of the American Bar Association Model Rules) is to be preferred.