Potato microtubers were treated with rindite to investigate the effect on dormancy breaking. Postharvest application of rindite by fumigation with 2 ml rindite for 48 hr or 4ml for 24 hr significantly reduced the dormancy period of potato microtubers using a 32 x 15 x 17 cm tightly sealed plastic box. Approximately 2 weeks after the treatments microtubers of all cultivars, Atlantic, Superior, Lemhi Russet, Red Dale and Kennebec started to sprout. The efficiency of the treatments were the greatest for the cv. Lemhi Russet, intermediate for cv. Superior and least for cv. Red Dale. In all cultivars of potato microtubers, more decay was observed the earlier rindite treatment occurred after harvesting, therefore potato microtubers should be treated with rindite at least 2 weeks after harvest when the skin of microtubers is mature. The data indicates that the dormancy of potato microtubers with well-matured skin can be effectively broken with an optimum treatment of rindite.