The Federal Emergency Management Agency (FEMA) Benefit-Cost Analysis (BCA) program, developed in the early 1990s, is used to determine the cost effectiveness of proposed mitigation projects for several FEMA mitigation grant programs. In 2008, FEMA collaborated with many Applicants and subapplicants on enhancements to update values in the software and to make it more efficient. The purpose of the BCA Reference Guide is to provide BCA software users with an overview of the grant programs, application development, benefits and costs, and the location of BCA guidance documents and helpful information. This guide also outlines sources of additional information needed to use the software to obtain a Benefit-Cost Ratio (BCR) for a single project or multiple projects. Hazard mitigation is any sustained action taken to reduce or eliminate long-term risk to people and property from natural hazards and their effects. This definition distinguishes actions that have a long-term impact from those that are more closely associated with immediate preparedness, response, and recovery activities. Hazard mitigation is the only phase of emergency management specifically dedicated to breaking the cycle of damage, reconstruction, and repeated damage. As such, States, Territories, Indian Tribal governments, and communities are encouraged to take advantage of the funding provided by Hazard Mitigation Assistance (HMA) programs in both the pre- and post-disaster periods. The Department of Homeland Security (DHS) and FEMA HMA programs provide a critical opportunity to reduce the risk to individuals and property from natural hazards, while simultaneously reducing reliance on Federal disaster funds. HMA guidance provides continuity between five FEMA mitigation grant programs: the Hazard Mitigation Grant Program (HMGP), Pre-Disaster Mitigation (PDM), Flood Mitigation Assistance (FMA), Repetitive Flood Claims (RFC), and Severe Repetitive Loss (SRL) programs. Each HMA program was authorized by a separate legislative action, and as such, each program differs slightly in scope and intent, but all of them provide significant opportunities to reduce or eliminate potential losses to State, Tribal, and local assets. HMGP may provide funds to States, Territories, Indian Tribal governments, local governments, and eligible private non-profits following a Presidential major disaster declaration. The PDM, FMA, RFC, and SRL programs may provide funds annually to States, Territories, Indian Tribal governments, and local governments. While the statutory origins of the programs differ, all share the common goal of reducing the risk of loss of life and property due to natural hazards. This publication was prepared with contributions by the URS Group, Inc., Gaithersburg, MD.