With the aim to find the best moment for pruning and determinate its inf1uence upon the yield on grapevine of the variety Black Burgundy, (Vitis labrusca) this thesis was made between the month of January and July 1999 in the District of San Antonio de Cumbaza, in the Province and Department of San Martín, situated at latitude South 06025', and longitude West 76025' and a height of 800 m above sea level. The experimental design used was the block completely al random (DBCA) wilh four repetitions and six treatments plus one proof. The experiment was carried out in a approximately 5-6 years old vineyard. We studied the rest days after harvesting until pruning on grapevine in the following way: T1 (pruning after 10 days). T2 (pruning after 15 days). T3 (pruning after 20 days - proof), T4 (pruning after 25 days), T5 (pruning after 30 days), TG (pruning after 35 days) and T7 (pruning after 4...