Laboratory experiments were carried out in the laboratory of Raw Materials for Food Agronomic and Livestock Research of Agronomy Faculty of the Lithuanian University of Agriculture in 2009. The investigation focused on Solanum tuberosum L. cv. ‘Goda’ and Solanum tuberosum L. cv. ‘Solara’. The aim of this paper was to identify the effect of high/low temperatures on the potato tuber sprout initiation at the apical dominance stage. Potato tubers were exposed to different temperatures (-10°C, +5°C, +30°C, +40°C, +50°C) and time (30, 60 and 90 min) regimes. Control potato tubers were stored in light, + 18°C and photoperiod of 12 h. Before the test, the tubers were numbered, fixed eyes number on the upper, middle and lower parts of the tubers. After obtaining these conditions it was assessed that germinated eyes were numbered on the upper, middle and lower parts of the tubers. The dynamics of tuber sprout was determined with an interval of 7-14-21 days after high / low temperatures effect, and all seed tubers were analyzed. The present study confirmed that high (+40, +50°C)/low (-10°C) temperatures broke the apical sprout and increasing of the quantity of sprouting eyes.