Storage of Irish potato tubers under 3 to 5° C, with air moisture remaining between 70 and 90%, affords good results in preventing sprouting of the tubers. As this treatment enables sugar formation in the tubers, the latter should not be used for consumption due to their unpalatability. At temperatures above 8°C sprouting occurs with loss of weight and other disadvantages. In the experiments herein reported two hormonlike substances were used to prevent sprouting under different temperatures. The chemical used were the methyl ester of alphanaphtaleneacetic acid (MENA) and 2, 3, 5, 6 tetrachloronitrobenzene (TCNB) mixed with talc. Under room temperatures practically little or no influence was shown by the treatments. However, under 8°C with an air moisture of 85%, MENA gave satisfactory results when tubers were stored during a period of 6 to 8 months. The results obtained were not alike for all varieties tested. It has also been found that some varieties show an increase in the percentage of soft rot in tubers receiving the hormonlike substances, mainly at room temperatures (20 to 25° C).