The UK Department of Health recently recommended that flour be fortified with folic acid, at 2400 μg/kg. The objectives of the present paper were: to determine the consequence of this on folic acid intake of adolescents; to determine the level of fortification necessary to achieve an intake of 400 μg/d in adolescent girls (the amount recommended periconceptionally); to estimate the consequence of fortification on folic acid intake of high flour consumers; and to report on folate intake of adolescents. Dietary intake of folate and flour were determined by analysis of an existing database of the diets of 379 English adolescents. The folic acid intake that would result from white flour fortification with folic acid at 2400 μg/kg was determined and the level of folic acid fortification necessary to achieve an intake of 400 μg/d in girls from this source was also calculated. Without flour fortification, 6·9 % of girls failed to reach the UK lower reference nutrient intake for total folate. Fortification of white flour with folic acid at 2400 μg/kg would result in an additional folic acid intake of 191(SEM 6) μg/d in girls. To ensure 97 % of girls received 400 μg/d from white flour, white flour would need to be fortified at a level of 10 430 μg/kg, resulting in intakes of 1260 μg/d from flour in the highest (97·5 centile) female white flour consumers and 1422 μg/d from flour in the highest (97·5 centile) male white flour consumers.