In the last few years, air pollution has become a major issue in some countries of Latin America and the Caribbean because of urban development and growing industrialization. In addition to industrial processes often concentrated in the cities, vehicle emission and stationary-source fuel combustion are the primary sources of air pollution. Although air-quality standards have been established in some Latin American countries, these are frequently exceeded. Adverse health effects of air pollution have been mainly associated with the following pollutants: sulfur dioxide and particulate matter, photochemical oxidants, nitrogen dioxide and carbon monoxide, and lead. Short-term as well as long-term effects can be expected at levels exceeding WHO guidelines. The Latin American urban areas most affected by anthropogenic pollutant emissions are: the area of São Paulo (Brazil), the city of Santiago (Chile) and the metropolitan area of Mexico City. However, situations similar to those prevailing in these cities could well occur in other cities of Latin America and the Caribbean. The population exposed to air-pollutant levels exceeding WHO guidelines can be estimated to 81 million or 26.5% of the total urban population of Latin America and 19% of its total population. These estimates correspond to 30 million children (0-14), 47 million adults (15-59) and 4 million elderly people (60+). To date a very limited number of epidemiological studies have been carried out to determine the potential health effects of air pollutants in Latin America. To obtain a rough estimate, a scenario was hypothesized in which subjects living in cities would be exposed to a given level of air pollutant, using data from the international literature to extrapolate the expected number of events in different strata of the hypothetical population. The estimated health effects are considerable and warrant priority control intervention. This is true although epidemiological studies are needed to evaluate the health impact of specific pollutant compounds as well as their interactions in Latin American populations exposed to high levels of pollution.