Investment disputes arise from time to time between investors and host states. In the event of such disputes, investors may turn to the International Center for Settlement of Investment Disputes for arbitration. One of the issues that can (still) arise during ICSID arbitration proceedings is the allocation of costs. Allocation of costs is a crucial aspect of any dispute resolution process, and ICSID arbitration is no exception. This article will show that a specific practice has been created in ICSID arbitration and outline the different approaches and principles used by ICSID arbitral tribunals when allocating costs. At the same time, the emphasis is placed both on possible problems of interpretation that may arise, as well as on some proposals to modify the investment treaties, so that the specific arbitration rules can be helped again by the treaty. For this article, a comparative research method was used that allowed a meta-analysis of the relevant arguments that can lead to a well-founded reasoning. Mostly primary sources were used, which were supplemented with secondary sources.