Summary We investigated the effect of Fe deficiency on the photosynthetic system of maize ( Zea mays var. Ganga 5). Chlorophyll content, PSI and PSII electron transport rates, P700, Q, cytochrome f, cytochrome b559 HP and CO 2 fixation by intact leaves show a decrease in Fe deficient plants. Maximum reduction is observed in the amount of cyt f, which may be the component that limits overall photosynthetic rates, instead of PSI, which has been described as the component most severely effected by Fe deficiency in other plants. Loss in carbon fixing ability is much greater than the loss of chlorophyll, but corresponds closely to the reduction in cytochrome content, further implicating cyt f as the limiting factor. Reaction centers of the photosystems were not reduced as much as other components, suggesting that in the case of Fe deficiency the plant shows selectivity when loss of electron transport components is imminent.