Four experiments were conducted to determine growth regulators, their concentrations and treatment time, rooting medium, and plant parts for optimum seedling propagation by stem cuttings in yacon (Polymnia sonchifolia Poepp. & Endl.). NAA was the most effective on rooting, and followed by IBA 2,4-D, and IAA. Dipping the base of cuttings in 50 or 100 ppm solutions of IBA increased rooting ratios. The 100 ppm solution of IBA was 14% higher than the 50 ppm solution for rooting ratios. Rooting medium with equal volumes of clay loam and sand was the most suitable for rooting of cuttings. Cuttings with both terminal bud and the first node or cuttings with both the first and second nodes were higher in rooting ratios than cuttings with only terminal bud or the first or second nodes. Days to rooting was not affected by plant parts.