Treatment of pieces of tuber of Dioscorea alata with ethephon promoted early sprouting. Effective dilutions varied from 0.08 to 1.28%. No toxic effects occurred at the highest concentration. Treatments were most effective early in the season but were also useful later even though natural sprouting became imminent. In comparison with recommended levels of ethylene chlorohydrin, ethephon stimulated sprouting equally. The maximum savings of time due to ethephon treatment was about 3 weeks.