This study addresses an alternative mechanism for the settlement of international tax disputes: so-called baseball arbitration. Although contracting states are able to adopt several formats to design alternative dispute resolution mechanisms, the author presents a concept of tax treaty baseball arbitration based on the approaches that have been envisaged by various international organizations and states. The article addresses in detail the main features and procedural rules related to baseball arbitration in international tax matters. Among these, special emphasis is placed on the accessory character, mandatory nature, enforceability and scope of the procedure. Other critical issues, such as the selection of the arbitrators, the presentation of offers and supporting arguments, taxpayer participation, secrecy and transparency of the procedure are analysed by anticipating possible practical, policy and legal difficulties that this new approach to tax treaty dispute settlement may raise.