Understanding the remitting practices of immigrants has taken on new urgency for banks seeking to tap the potential of this burgeoning market as well as for economists, who note that remittance inflows into developing nations often match or exceed traditional sources of foreign currency earnings. ; To gain an understanding of who remits, how much and why they remit, and what transfer mechanisms they use, the authors review the basic trends in remittance transfers from Mexican immigrants in the United States—who account for about one-third of U.S. immigrants—to their families in Mexico. ; Using survey data from the Mexican Migration Project and the Encuesta Sobre Migración en la Frontera Norte de México, the authors examine the demographic characteristics and the remittance and banking behavior of Mexicans who have migrated to the United States. The surveys encompass nearly 11,000 documented and undocumented immigrants. ; The authors’ analysis indicates that immigrants’ motives for remitting to their home communities are at least as varied as their reasons for migrating. Altruism, investment, and mitigating risk appear to play important roles in explaining immigrants’ remitting behavior. The propensity to remit seems to be greater among immigrants who are undocumented, those who have left dependents in Mexico, those with lower levels of education and English skills, and the unbanked, the authors conclude. Over the 1993–2000 period, the use of money transfer firms to make remittance payments declined from 77 percent to 66 percent of all transfers while banks’ market share increased from 4 percent to 17 percent.