Excerpts from the Foreword: In 1946 the Federal Inter-Agency River Basin Committee appointed a Subcommittee on Benefits and Costs for the purpose of formulating mutually acceptable principles and procedures for determining benefits and costs for water resources projects. After consideration of the benefit-cost practices currently in use and of an objective analysis of the economics of river-basin projects uninfluenced by current practices and legal or administrative limitations, the Subcommittee considered various approaches to the problem and presented its conclusions in this report Proposed Practices for Economic Analysis of River Basin Projects. There are appended summaries of previous Subcommittee reports on the qualitative aspects and measurement aspects of benefit-cost practices which were in use when the reports were issued.