The objective of this study was evaluate, the response of the beginning of the Partial Root-Zone Drying Irrigation (PRD) in the performance of the sweet potato culture, for both the Huambachero and Paramonguino varieties. For this investigation drip irrigation was applied in two ways; with 100% of irrigation sheet and PRD with 50% of irrigation sheet, with three different beginnings of PRD; at 23, 33 and 45 days after sowing, watered with a frequency of 2 days. The yields for the control treatment were 42,1 t.ha-1 and 39,2 t.ha-1 for both the Huambachero and Paramonguino varieties and for the early PRD of 23, 33 and 45 days of 37,4 t.ha-1 , 32,7 t.ha-1 and 35,1 t.ha-1 , in the Huambachero variety and 30,0 t.ha-1 , 31,4 t.ha-1 and 32,6 t.ha-1 in the Paramonguino variety.The water application for both varieties was: 5368,9 m3 .ha-1 in the control treatment, 3185,54m3 .ha-1 , 3429,47 m3 .ha...