Evidence – its marshalling, disclosure and presentation – lies at the heart of many, if not most, international arbitration proceedings. Yet, perhaps more than any other aspect of arbitral practice, evidentiary issues lay bare the significant divergences between the common and civil law traditions. As result, evidentiary questions can sometimes be among the most contentious that arise in an international arbitration, particularly when a dispute involves parties and/or counsel from different sides of the common law/civil law divide.In this chapter, we outline the process by which evidence is used in international arbitration and highlight some particularly thorny issues that can arise, including in relation to the document disclosure process, the admissibility of evidence and the use of evidence at an evidentiary hearing.It is important that parties and counsel consider these evidentiary issues carefully – and early in the arbitral process. Although every tribunal is different, international arbitration is fundamentally party-driven.Parties should therefore be proactive in fostering an efficient, effective, and fair process as it relates to the gathering, production and use of evidence in an international arbitration proceeding.