The Amu Darya is governed by various bilateral and regional treaties: between Afghanistan and Russia/the former USSR and among the Central Asian Republics (CARs). The former are boundary treaties and do not cover the use of the Amu Darya, and the latter are, inter alia, water-sharing agreements that govern the use of water. This paper examines the current legal regime governing the Amu Darya. It outlines one specific question: What are the legal implications for Afghanistan of its exclusion from the regional legal framework governing the apportionment and utilization of the Amu Darya? This paper argues that without Afghanistan's inclusion in the regional water agreements or organizations governing the Amu Darya, no Central Asian regional water agreement or organization is complete. The paper makes two arguments. First, the equitable and reasonable utilization principle has the precedence over the no harm rule and it gives all riparian states a right to an equitable share in shared watercourse, therefore the downstream CARs cannot prevent upstream Afghanistan from developing their water resources. Second, even though Afghanistan is not a party to the agreements governing the Amu Darya, the country can be affected or harmed by downstream uses of water, as Afghanistan's future use of the Amu Darya can be foreclosed or limited. Although Afghanistan can recourse to the 1997 UN Convention for the allocation of Amu Darya waters, the convention does not serve its interests. There are some arguments that the factors determining equitable and reasonable utilization in the 1997 UN Convention refer to past use, the concept of equitable and reasonable utilization protects the interests of early developers (the CARs) against those of late developers (Afghanistan) in regards to the utilization of water resources.