In June 2009, the French Institute for Public Health Surveillance (InVS) conducted an estimate of the number of people infected with Trypanosoma cruzi and those at risk of developing chronic Chagasic cardiomyopathy to quantify the burden of this disease in metropolitan France and its overseas departments, excluding French Guiana. Various at-risk groups were identified: Latin American (LA) immigrants [naturalized citizens, immigrants with and without legal status, adopted children], children born in France to LA mothers, French Guianese residing in metropolitan France, expatriates, and travelers who have stayed in endemic areas. Country-specific prevalence rates were applied to official demographic data from the International Adoption Agency, the Tourism Directorate, and the Ministries of Finance, Foreign Affairs, and Immigration. Of approximately 157,000 people potentially exposed to Chagas disease, an estimated 1,464 (range: 895–2,619) are infected, of whom between 63 and 555 are likely to develop heart disease. These results corroborate the initial estimates produced by the InVS and those by Guerri-Guttenberg, which were conducted for various European countries. The lack of reliable data regarding undocumented immigrants introduces a significant bias. Taking this group into account could significantly increase the burden of the disease in France. (R.A.)