The effects of gibberellic acid (GA3) concentration, treatment interval, and treatment commencement timing on the development of the main vegetative shoots, aerial and new tubers, and inflorescences (spikes) were investigated in Chinese yam (Dioscorea oppositifolia L.) 'Ichoimo'. Foliar applications of 25, 50, 100, and 200 mg L-1 of GA3 (GA3 25, GA3 50, GA3 100, and GA3 200) was carried out at 1-week intervals after shoot emergence, and the subsequent foliar applications of GA3 (100 mg L-1) were carried out at 1-, 2-, and 4-week (GA3 E1W, GA3 E2W, and GA3 E4W) intervals after shoot emergence. The last foliar application of GA3 (100 mg L-1) was carried out at 1, 2, 4, and 8 weeks (GA3 A1W, GA3 A2W, GA3 A4W, and GA3 A8W) after emergence. Following the above applications, the final fresh weight of the aerial tubers was observed to be higher in the control plants than in both the GA3 25- to GA3 200- and GA 3 E1W- to GA3 E4W-treated plants. However, the GA 3 25- to GA3 100- and GA3 E1W- to GA 3 E4W-treated plants produced new tubers with the highest final fresh weight. Similarly, aerial tubers with the highest final fresh weight were harvested from the control plants. These were followed by the GA3 A8W-treated plants; the GA3 A1W- to GA3 A4W-treated plants produced aerial tubers with the lowest final fresh weight. However, the GA3 A1W- to GA3 A4W-treated plants produced new tubers with the highest final fresh weight. The ratio of the development of spikes in every GA3-treated plant was slightly lower than that in the control plants.