Introduction Farmers continue to search for ways to increase corn and soybean yields, including the use of plant growth regulators. Plant growth regulators, such as gibberellic acid and cytokinins, are organic compounds that modify plant growth processes at very low concentrations. Gibberellic acids control cell elongation and division in plant shoots. Cytokinins affect cell division, cell enlargement, senescence, and transport of amino acids in plants. Plant growth regulators are more commonly used on fruit and vegetable crops than on grain crops. The purpose of these trials was to investigate the effect of plant growth regulators on corn and soybean yield.