For observing the consequences of iron (Fe) fortified spinach (Spinacia oleracea L.) cultivars on growth and their uptake capability for the nutrient elements, an experiment was conducted under greenhouse conditions. Iron doses of 30, 60, 90, 120 and 150 mu M were applied to spinach cultivars in re-circulated hydroponic systems. Insufficient amounts of Fe has caused magnesium (Mg) accumulation in the roots and not only inhibited the translocation of Mg from roots to leaves but also reduced the up taken amounts of other nutrients. Increasing the doses of Fe, encouraged growth of the plants, aroused the yield of dry matter, SPAD values, and uptake of the nutrients of spinach leaves up to 120 mu M Fe doses (p < 0.01). However the effect of highest dose of Fe (150 mu M) was found negative. Fortification of spinach with Fe resulted as an accumulation of Fe, copper (Cu) and manganese (Mn) in the roots. Because of the contrary relations with the other nutrients, a special attention must be paid during fortifying the plants with iron.