Chemical growth regulators were applied in early fall to 1-year-old ‘Delicious’ apple trees (Malus domestica Borkh.) to evaluate cold hardiness and cold injury during late fall to late winter. Evaluations were made by the conductivity test and expressed as the percentage of electrolytes. Of the 18 chemicals tested, CGA-15281 (500 ppm) showed the most promise for increasing cold hardiness, especially in November. During freeze tests in November or February of 1976, AMO-1618 (1000 ppm), GA3 and GA3 + fluoridamid (500 and 6000 ppm, respectively), and Thidiazuron (100 ppm) induced significantly greater cold hardiness than the controls. When tested separately or in combination with other chemicals, ancymidol, CGA-15281, DEPEG, PP 528, and NIA-10637 produced slightly more cold hardiness relative to the controls in more than 50% of the tests. Daminozide, ethephon, GA3, glyphosine, and UBI-P293 were the least effective chemicals for inducing cold hardiness.