Corn grain which contained radioactive phosphorus, taken up during its growth, was desired for a poultry feeding investigation. With this desired product it would be possible to carry on the investigation and also others requiring iso-topic tracer elements for their soln. A conventional gravel culture procedure was employed in growing hybrid field corn to maturity. Radioactive P was applied in tap water which replaced the nutrient soln. during the early milk stage of the corn kernels. The corn reached maturity a month later and showed strong activity in all its parts with the grain most active of all. The ground corn grain averaged 2,800 counts per min. per 100 mg. Ca phytate isolated from the corn averaged 47,040 counts per min. for a 100-mg. sample.