Minitubers are progeny tubers produced on in vitro plantlets after tralanting these plantlets in the greenhouse. In this way, Minituber is producing healthy plantlets by removing viruses, however, its dormancy period is longer than normal seed tubers. Minitubers dormancy period can be removing by physical and chemical methods. A number of chemicals that are used to break dormancy, are dangerous for human health and the environment. While, the breakage of dormancy by physical methods such as modified atmospheres requires expensive facilities and long periods. Plant growth regulations are producing naturally in plants and treating minitubers with these materials is a safe and confident method. In Iran, use of GA3 to break dormancy of potato minitubers is very common. However, the effect of GA3 on dormancy duration in seed tubers is cultivar dependent. Polyamines are essential for the normal growth and development of all cells, and its can be effective for breaking dormancy in minitubers. To test this hypothesis, a factorial experiment was conducted based on completely randomized design in four replicates. Minitubers of three cultivars (Marfona, Santeh, and Jelly) treated with three types of polyamines including spermine, spermidine, and putrescine in different concentrations (30, 45, and 60 mg/l) and GA3 (50 mg/l) and distilled water as controls. After dormancy breaking, attributes like as days to sprouting, length and diameter of the sprout, weight loss, and sprout number measured. In all cultivars, applying GA3 caused faster breakage of dormancy, but polyamines were no effective in breakage of dormancy than control. Also, results showed that polyamines treatments did not have a significant effect on the length and diameter of the dominant sprouts compared to the control, but the longest length and thinnest diameter of the dominant buds were observed in gibberellic acid treatment, as compared to other treatments. Among polyamines, spermine treatment significantly increased the number of sprouts compared than spermidine treatment. Comparing polyamines with controls, gibberellin treatment had a significant difference in most of characteristics with putrescine and spermine treatments. In polyamines treatments, the lowest and highest apparent wilting is related to spermidine and putrescin treatment, respectively. Moreover, in the controls treatment, the highest apparent wilt was related to gibberellic acid treatment. Comparing polyamines with controls, results showed that the least wilt was achieved in spermidine treatment and distilled water control. Dormancy breakage correlated with higher weight loss and an increase in the rate of respiration of tubers following sprout emergence. Comparing between cultivars, results indicated that Jelly had the greatest length and diameter of buds and faster breakage of dormancy. Keywords: Spermine, spermidine, putrescine, polyamines, gibberellic acid, minituber, breaking dormancy