Confidentiality is generally regarded as important to the success of mediation and is the subject of a new Uniform State Law. Professor Ellen Deason analyses the difficulties in predicting the extent of the protection mediation communications will receive in any future dispute at the time of a mediation, when the parties' expectations for confidentiality most affect their behavior. Uncertainty regarding the forum for a future dispute, variability in state law, and the undeveloped status of federal law all contribute to unpredictability. Predictability is especially complex in federal court, where multiple choice-of-law rules may apply and the appropriate analysis depends on which evidentiary mechanism protects the mediation's confidentiality. Under current law, parties who engage in mediation in a federal court program cannot assume that the mediation's confidentiality will necessarily be determined by the court rules that govern the program. Deason explores means for increasing predictability through best practices and legal rules and examines the limitations of these approaches.