Many countries are facing a retirement savings crisis. In the United States, for example, the fraction of workers at risk of having inadequate funds to maintain their lifestyle through retirement is estimated to have increased from 31% to 53% from 1983 to 2010 (1). Roughly half of U.S. employees (78 million) have no access to retirement plans at their workplace (2). Fortunately, there are solutions to these problems. We simply have to change the choice architecture of retirement plans by utilizing the findings of behavioral economics research (3) and make such plans available to all workers. We describe a large-scale field demonstration of the potential impact of such research-based changes in how we save.