The effect of postharvest application of gibberellic acid and two inhibitors of gibberellin biosynthesis on the dormancy and respiration of tubers grown from true potato seed was studied. The potato hybrid ‘Chacasina-F1’ (provided by C.I.P., Lima) was cultivated during two seasons: spring (sown in January) and autumn (sown in September). Ten days after harvest, tubers were sliced at the point of stolon detachment and immersed in aqueous solutions of gibberellic acid – GA (5 mg/L), chlormequat chloride – CCC (100 mg/L) and daminozide (100 mg/L) or water (control) for 3 h. Tubers were then stored in the dark at 20°C for 30 days and bud germination, tuber respiration and weight loss were recorded at 5-day intervals. In addition, tubers were planted in moist peat and sprout emergence recorded over 60 days. Gibberellic acid promoted sprouting in tubers stored in air or planted in peat. Moreover, GA-treated tubers stored in air exhibited higher rates of respiration and weight loss than the control. This result was similar for tubers from both sowings. In contrast, the two inhibitors of gibberellin biosynthesis (CCC and daminozide) failed to affect sprouting, irrespective of whether tubers were stored in air or planted in peat. There was also no effect of these inhibitors on tuber respiration and weight loss. We conclude that GA may be applied postharvest to break dormancy and so promote sprouting for early planting, but postharvest application of CCC and daminozide does not extend the storage life of seed tubers and so has no commercial application.