This report profiles, for the first time, the national phenomenon of day labor in the United States. Men and women looking for employment in open-air markets by the side of the road, at busy intersections, in front of home improvement stores and in other public spaces are ubiquitous in cities across the nation. The circumstances that give rise to this labor market are complex and poorly understood. In this report, we analyze data from the National Day Labor Survey, the first systematic and scientific study of the day-labor sector and its workforce in the United States. This portrait of day labor in the United States is based on a national survey of 2,660 day laborers. These workers were randomly selected at 264 hiring sites in 139 municipalities in 20 states and the District of Columbia. The sheer number of these sites, combined with their presence in every region in the country, reflects the enormous breadth of this labor market niche. Findings reveal that the day-labor market is rife with violations of workers' rights. Day laborers are regularly denied payment for their work, many are subjected to demonstrably hazardous job sites, and most endure insults and abuses by employers. The growth of day-labor hiring sites combined with rising levels of workers' rights violations is a national trend that warrants attention from policy makers at all levels of government.