The process of establishing facts in international arbitration is of essence. Scholars and practitioners alike have often discussed issues such as taking of evidence and related questions. Yet, little attention has been paid to the burden and standard of proof in that context.  The general consensus on the definition, scope and nature of the burden and standard of proof in international arbitration remains indeed limited. Authorities disagree on whether these concepts are procedural issues or questions of substantive law. The ambiguous nature of the burden and standard of proof gives rise to difficult questions in conflict-of-laws cases. Attempts have been made to bridge the differences between the procedural and substantive approach by suggesting application of an international standard of the burden and standard of proof. It remains, nonetheless, to be seen whether the burden and standard of proof emerge as international standard. This article suggests that a pragmatic approach be taken in order to identify applicable burden and standard of proof rules. Such process should be not confined to any category of law, be it substantive or procedural, but should instead cover the entire law of the jurisdiction whose (substantive) law is the law of the arbitration. That approach may ensure that a balance is struck between the principles of flexibility and efficiency on the one hand, and foreseeability and legal certainty on the other.