This article deals with multi-tier dispute resolution clauses incorporating both mediation and arbitration together under Turkish Law. I use the terminology of “med-arb” not only for the situation where the mediator acts as an arbitrator, but rather in a general meaning covering all instances where the arbitration is commenced following an unsuccessful mediation. The purpose of this article is to discuss the validity of the med-arb agreements, the consequences of starting arbitration before the mediation fails, the effects of the mediation proceedings and of the mediator acting as an arbitrator on the arbitration that follows the mediation as well as the admissibility of the documents and factual evidence exchanged at the mediation. For the purpose of this article, the comparative laws, international ethics rules, international guidelines on the conflict of interest and admissibility of evidence are reviewed along with Turkish law. Turkish Code on Mediation in Civil Law Disputes stipulates some provisions related to the med-arb. These provisions shall apply equally to both domestic and international arbitrations where the place of arbitration is Turkey. Following the jurisprudence of the Turkish Supreme Court, a med-arb agreement is valid only if it reflects, without doubt, both parties’ consents to the arbitration following the failure of the mediation proceedings. Therefore, a multi-tier dispute resolution clause subject to Turkish law needs to be drawn carefully. In this respect IBA Guidelines for Drafting International Arbitration Clauses are of assistance. In cases where one of the parties commences arbitration without a recourse to mediation first, the arbitral tribunal should make a decision on the admissibility of the claim. There is no direct provision related to the question of admissibility under Turkish law. Under Turkish law, in parallel with the practice of international arbitration, the tribunal has to interpret the med-arb agreement to make a decision on the question of whether the recourse to mediation is a pre-condition of the arbitration. If the mediation is a pre-condition, then the tribunal should suspend the arbitral proceedings and direct the parties to the mediation. However, in the case that the mediation fails, the tribunal may resume the arbitral proceedings. There is nothing under Turkish law suggesting that a precondition of arbitration is a jurisdictional issue rather than an admissibility issue. The advantages of the med-arb are subject to heated debates among people holding different perspectives. Such advantages are controversial since when a dispute arises and the arbitration starts without a recourse to mediation, the respondent may object to the jurisdiction of the tribunal or to the admissibility of the claim relying on the fact that the pre-condition to try mediation first is not met. Such an objection may cause arbitration to be delayed and/or the costs of arbitration to increase. Therefore, before opting for a med-arb agreement the parties should evaluate the possibility of settling their dispute at the Med-arb. The parties who are able to consider their commercial interests do not need a med-arb agreement as they are able to settle the disputes without the assistance of a mediator. They first try to settle the dispute, in some cases for years, and to avoid adjudication by an arbitral tribunal. They only start arbitration when there is no possibility of settlement of their dispute and of saving their commercial alliance. In such cases, med-arb agreements become a tool to delay the proceedings and increase the costs for the claimant to force him or her to give up his or her claim. Having said that, for the parties who are unable to consider their commercial interest and unable to avoid adjudication, med-arb agreement may be the right dispute resolution clause. In a med-arb agreement, the parties may wish the mediator to act as their arbitrator if the mediation fails. Neither the Turkish Code of Mediation in Civil Disputes nor the Turkish International Arbitration Code prevents a mediator to act as an arbitrator. Turkish Ethics Rules for Mediators stipulate that a mediator may act as an arbitrator only if the parties have agreement in writing. Therefore, any mediator to act as arbitrator needs to have the parties’ written consent. In international mediation and arbitration practices, the scholars and practitioners widely accept that having an arbitrator who previously acted as a mediator generates a number of serious risks and concerns. First of all, the mediator-arbitrator may not protect his or her impartiality in the arbitration because of the facts that she or he became aware of during the mediation. Secondly, the mediator-arbitrator may rely on the confidential information exchanged in caucus while making the award. Thirdly, the mediator may be too willing to act as an arbitrator and as a result the mediation may prematurely fail. Finally, the mediator may abuse his or her powers and force the parties to settle their disputes as the mediator suggests. The parties may feel that if they are not able to settle their dispute and proceed to the arbitration, the mediator-arbitrator would make an arbitral award in parallel of the recommendations at the mediation phase. Considering the severity of the consequences, if the parties agree to have an arbitrator who previously acted as their mediator, they need to be aware of such consequences and they need to make an informed decision accordingly . The Turkish Code of Mediation in Civil Law Disputes restrains the ability of the mediator-arbitrator to rely on the documents produced during the mediation for the purpose of settlement and defines which documents are in this category. In the case where the mediator-arbitrator relies on these documents while making the award, depending on the extent the document or information has a bearing on the award, the arbitral award may be cancelled, or its enforcement may be refused. In November 2019, Istanbul Arbitration Center (ISTAC) introduced its Medarb Rules. ISTAC Med-arb Rules are the first published institutional Med-arb rules. ISTAC Med-arb Rules reflect the best practices in international mediation – arbitration. I believe that ISTAC Med-arb Rules will be welcomed in the field of international dispute resolution.