The length of tuber dormancy of potato (Solanum tuberosum L.) is an important property of cultivars, which significantly determines the duration of storage period, the storage conditions, the economy of storage and the earliest time of planting. Potato cultivars can largely differ in the duration of dormancy period. Under temperate climatic conditions, longer dormancy is more advantageous. However, in case of multiple planting within one calendar year or in case of specific needs, it can be necessary to artificially break the dormancy of tubers. In this study, we investigated the effect of chemical treatments on the tuber dormancy of three Hungarian potato cultivars (Balatoni rózsa, Démon, Botond) having different dormancy periods. The experiment was conducted in three consecutive years (growing periods). Treatments were performed using gibberellic acid, benzyl-adenine and Rindite in different concentrations and combinations. Results showed that the treatments largely influenced the length of tuber dormancy. Rindite and its combination with gibberellic acid treatments largely and significantly reduced the dormancy period for all the cultivars in all growing season, with an average 65% reduction (1906 to 669 °C). Treatments had the greatest impact on the cultivar Balatoni rózsa, with an average 33% reduction of dormancy, while they had the least impact on the cultivar Démon, with an average 25% reduction. We did not observe significant relationship between cultivar maturity type and the reduction of tuber dormancy. We found that the weather conditions of growing period influence the duration of dormancy and the efficiency of chemical treatments.