The objective of this paper was to determine the accumulation of glycoalkaloids in potato tubers caused by a stress generated by mechanical damage and light exposure. The experiment was carried out in the years 2002 and 2003; six potato cultivars were investigated: Aster, Denar, Ditta, Irga, Żagiel, and Wawrzyn. It was noted that the mechanical damage and light exposure caused the increase in the synthesis of glycoalkaloids. The increase in the levels of those compounds in the damaged and, simultaneously, light-exposed tubers was twice as high as in the case when each of those two factors would have interacted separately. When potato tubers were stored at a temperature of 8°C, the content of glycoalkaloids grew from 12 to 45 mg/kg fresh weight. The highest amount of glycoalkaloids was found in the external part of potato tubers: in their peel and just beneath the peel. In the peeled potatoes, the content of glycoalkaloids in potato tubers was by 54% lower.