The Housing Assistance Supply Experiment was designed to monitor market and community response to a full-scale housing allowance program for low-income households. This study examines factors affecting an eligible household's decision to apply for a housing allowance during the first program year in St. Joseph County, Indiana. Using data on such households, it tests a two-stage model of the enrollment choice. The first stage analyzes how people learned about the program; the second analyzes factors affecting the decision to apply for those who were program-aware. Results show that lack of program information precluded 13 percent from applying. Word-of-mouth communication has the most potential for reducing nonparticipation in this group. Among program-aware eligibles, the main impediments to enrollment are insufficient information, anticipated cost of required housing repairs, and aversion to government aid. Those most likely to apply have lower incomes, a great preference for space, and live in crowded quarters.