Maise meal fortified with folic acid was administered to subjects in late pregnancy in a daily dose of either 500 or 300 mug of folic acid. Changes in hematological and folate nutritonal status were compared to those in subjects receiving 300 mug folic acid/day in tablet form, and also in subjects in a previous study who received unfortified maize meal (control group) or meal containing 1,000 mug folic acid/day. In all groups receiving folic acid, red cell and serum folate levels rose progressively, and the rate of rise increased with increasing doses of folic acid. Maize meal containing a daily dose of 500 mug folic acid produced an effect similar to that of 300 mug daily in tablet form. Maize containing 300 mug added folic acid daily was effective in preventing the progression of folate depletion in late pregnancy.