Organoleptic tests were carried out in 1959 and 1960 to determine the possible occurrence of off-flavor in potato tubers, caused by the application of insecticides to the soil where the plants were grown, on the seed, and on the plant leaves. In 1959 the treated samples were compared against the control by the triangular test; in 1960, in a lattice square 3x3 with four replications. The insecticides applied to the soil in 1959 were as fallows: BHC (gamma-isomer), Heptaclor, Aldrin, Parathion, and Lindane. BHC induced a very strong mold-like «rmusty» off-flavor, significant in relation to the control at the 1% level. Parathion and Lindane induced an unidentified off-flavor, called by the testers as a medicin odor, but not differing statistically from the control; Heptaclor and Aldrin did not confer any off-flavor. Also in 1959 the samples from the plots which received seed treatment with Disyston and leaf spraying with Rhodiatox and Metasystox were compared with a control to which charcoal had been added and with another, without theatment. The results were statistically significant in relation to the control for Disyston and Matasystox, but not for Rhodiatox. Both Disyston and Metasystox conferred a medicin odor and a slight fiery taste to the puree. The 1960 insecticides, applied in normal and double dosages, were Lindane, Toxafeno, Heptaclor, and Aldrin. Both dosages of Lindane conferred the same musty off-flavor to the potato puree, this results differing from the control and normal toxafeno at the 1% level. The other treatments were not statistically different from the control.