The present work was carried out in order to study the influence of low temperatures on germination and vigor of true potato (Solanum tuberosum L., cv. Apuã) seeds. Two temperatures (5 and 10°C) and eight frigorification periods (6, 12, 18, 24, 30, 36, 42 and 48 hours) were used. The experimental design was a factorial 2 x 8 plus an additional treatment without frigorification (control) with the treatments arranged as completely randomized and four replications. The standard germination (four 50 seed samples, gerbox, 20-30°C) and vigor (first count and speed of germination) were evaluated. It was observed that the germination as weIl as the vigor increased with the temperature and frigorification period, thus it can be concluded that the frigorification can be used to break dormancy of true potato seed.