This study provides information on the caffeine intakes of a representative sample of the US population using the US Department of Agriculture 1994 to 1996 and 1998 Continuing Survey of Food Intakes by Individuals. The percentage of caffeine consumers of the total sample (N=18,081) and by age and sex groups and for pregnant women were determined. Among caffeine consumers (n=15,716), the following were determined: mean intakes of caffeine (milligrams per day and milligrams per kilogram per day) for all caffeine consumers, as well as for each age and sex group and pregnant women; mean intakes (milligrams per day) of caffeine by food and beverage sources; and the percent contribution of each food and beverage category to total caffeine intake for all caffeine consumers, as well as each age and sex group and pregnant women. Eight-seven percent of the sample consumed food and beverages containing caffeine. On average, caffeine consumers' intakes were 193 mg caffeine per day and 1.2 mg caffeine per kilogram of body weight per day. As age increased, caffeine consumption increased among people aged 2 to 54 years. Men and women aged 35 to 64 years were among the highest consumers of caffeine. Major sources of caffeine were coffee (71%), soft drinks (16%), and tea (12%). Coffee was the major source of caffeine in the diets of adults, whereas soft drinks were the primary source for children and teens.