Abstract: This article will examine the grounds for challenging an arbitral award in the United States ("U.S.") by focusing particularly on the approach taken by U.S. courts with regards to the application of the doctrine of "manifest disregard of the law" as a basis for vacatur of an arbitral award. This article proceeds in eight sections. Section one will provide a brief introduction to the subject. Section two will present the grounds upon which an award may be challenged in the U.S. under the Federal Arbitration Act and the United Nations Convention on the Recognition and Enforcement of Foreign Arbitral Awards. Section three will explain the different types of arbitral awards within the U.S and its characteristics. Section four will relate research about the development of the doctrine of "manifest disregard" as a non-statutory ground to vacate an award and its conflicting interpretation and application throughout the years by U.S. federal circuit courts. Section five, will illustrate what types of awards could be subject to the "manifest disregard" doctrine in the U.S. Section six will discuss, counsels' "manifest disregard" of the law. Section seven, will examine similar grounds to vacate an award outside of the U.S. Lastly, section eight will provide a brief conclusion.