Patrimonio Hoy is a program targeting the housing needs of the low-income population by CEMEX, a major Mexican company and a leading global cement producer. Originally conceived as a project to understand the customers in the self-construction segment better, a major component of Mexican home-building concentrated in low-income neighborhoods, Patrimonio Hoy has generated recognition and good will for the company. Its innovative approach reduces significantly the cost and time needed by the poor to improve their housing. Begun in 1998, the program has reached break-even in 2004, with strong prospects of growth in the future. The president of CEMEX North America wonders whether the program should be turned into a major line of business for the company. Provides a good understanding of financing mechanisms available to home builders in Mexico and represents an interesting application of microfinance and product design to open a new market segment based on the needs of low-income customers.