The effects of breakfast cereal composition, breakfast cereal processing, and breakfast meal composition on relative iron availability from breakfast meals were estimated using an in vitro method. Addition of wheat bran and germ to cereals and meals reduced iron availability. Presweetening caused a slight increase in iron availability. Comparisons among meals containing cereals that were similar except for type of processing showed that processing may affect iron availability. Addition of orange juice to breakfast meals caused a dramatic enhancement of iron availability. Ascorbic acid fortified apple and grape juice increased iron availability but the effect was small compared with the orange juice effect. Studies with purified organic acids showed that ascrobic and citric acids present in the juices caused the observed enhancement of iron availability. Citric acid was a more potent enhancer than ascorbic acid.