Symptoms of zinc deficiency, characterized by leaf chlorosis, have been noticed on corn plants growing on certain types of soil in the state of São Paulo. These symptoms appear during the plants' first stage of growth and disappear later as they grow older. To study the effect of zinc applications as a corrective for this deficiency, o field experiment was carried out on a type of soil on which corn plants usually showed zinc deficiency symptoms. This experiment was located at Mogi-Mirim, São Paulo, on a soil of the Glacial type. The results of the experiment indicated that zinc applied as a spray on the leaves had no effect on yield when compared with the controls, although mild to severe deficiency symptoms were present. Zinc sulphate applied in a mixture with the fertilizers at planting time prevented the appearance of deficiency symptoms and apparently induced o slight increase in yield.