The monitoring of illicit coca bush cultivation is based on the interpretation and digital processing of LANDSAT, ASTER, and SPOT satellite images. The 2003 census of coca cultivation analyzed 39 LANDSAT images, 45 ASTER images, and 4 SPOT images. All images were taken between September 2003 and February 2004. The most encouraging finding was that coca cultivation in Colombia declined from 102,000 hectares (a hectare is 2.47 acres) in 2002 to 86,000 hectares in 2003, a 16-percent decline that was not matched in the other Andean countries. This is the third consecutive annual decrease since 2000, producing a total reduction of the area under coca cultivation by 47 percent. At the regional level, the most dramatic results were recorded in Putumayo, once the most important coca producing area in the country. It showed a reduction of 6,000 hectares in 2003, a 45-percent reduction. This report concludes that these reductions in coca cultivation have been achieved by investments in providing former coca farmers with opportunities for sustainable livelihoods as an alternative to coca farming, accompanied by fumigation and law enforcement campaigns. Colombia, however, remains the top coca producing country in the world. The report advises that the roots of Colombia's drug problems lie in social and economic disruption, continued armed conflict funded by drug profits, and weak social capital. The strong commitment of the Colombian Government in addressing these factors must be matched by international help to reduce the economic hardship of the rural poor and strategies to reduce cocaine-consuming markets. Data are provided on coca yield and production, coca prices, opium poppy cultivation, opium and heroin production and prices, aerial spraying, and drug seizures. 36 tables, 27 figures, and appended supplementary data and maps