In this chapter, we address the epidemiology of homelessness among US Veterans, including a discussion of the methodological challenges relevant to the enumeration and description of homelessness as well as a presentation of current estimates and trends in homelessness among Veterans. The chapter begins with a brief overview of homelessness among Veterans historically, with the remainder of the chapter focusing on the prevalence and incidence of homelessness among Veterans over the past decade. The methodological considerations discussed in this chapter include issues surrounding conceptual definitions of homelessness, implications related to the time frame used for estimates, a comparison between point prevalence, period prevalence, and incidence, and a description of various approaches for using primary and administrative data to estimate the magnitude and composition of homelessness among Veterans. Finally, we present recent national estimates of the prevalence and incidence of homelessness among Veterans, along with a summary of trends over time, and segmentation of estimates by demographic, geographic, and housing status characteristics.