Intakes of dietary fiber and its different components have been measured in a random sample of the population in Cambridgeshire, England and compared with data from the British National Food Survey. Sixty-three men and women ages 20 to 80 were included in the sample. Total dietary fiber intake was 19.9 +/- 5.3 g/day compared with the calculated value of 19.7 g/day from the 1976 National Food Survey. There was a 4-fold range in fiber intake from 8 to 32 g/day; no significant trends with age or between men and women were detected. Vegetables supplied the majority of the fiber (41.3%); cereals 30.5%, and fruit and mixed sources 28.2%. Of the components of dietary fiber noncellulosic polysaccharide, cellulose, and lignin intakes were 13.8, 4.7, and 1.4 g/day, respectively. In the noncellulosic fraction, hexoses contributed 7.4 g, pentoses and uronic acids 3.3 and 3.0 g. Vegetables and unrefined cereals were the main sources of pentose. These intakes are low in comparison with limited international data from developing countries and of a similar order to those known in dietary experiments to produce low stool weights, slow transit time, and concentrated feces. They could readily be increased by simple dietary changes.