The current research was conducted to determine the effects of different potassium (K) and iron (Fe) rates on the growth and some micro nutrient uptake of maize. For this purpose, five K (1, 2, 4, 6 and 8 mM) and four Fe (30, 60, 90 and 120 mu M) doses were applied to maize (Zea mays L. cv. BSC 6661) plants in a re-circulated hydroponic system. Increasing K and Fe levels had positive effects on dry weight of the maize shoots and roots. The total Fe and active Fe concentrations and their uptake increased with the increasing levels of Fe and K, but these amounts decreased with the highest K dose. The addition of increasing levels of K and Fe decreased the Mn, Zn and Cu concentrations in both shoots and roots of maize. Although the lowest doses of K and Fe have positive effects, the elevated K and Fe doses decreased the uptake of Mn, Zn, Cu and Na in both roots and shoots.