The objective of this study was to evaluate the productivity of three cassava ethnovarieties, whose cuttings were planted in two positions: vertical and horizontal in the municipality of Alta Floresta, Mato Grosso state (MT), Brazil. The plants which originated from vertically planted cuttings gave rise to roots with a larger length and larger diameter when compared to those planted horizontally. Root yield was higher for the Cacau Roxa ethnovariety (13.79 t/ha), and produced 30.57% more than Cassava Amarela and 56.12% more when compared to Cassava for frying without being boiled first. This higher yield can also be observed for the weight of the aboveground part of the plant (10.60 t/ha). In both planting positions there was a positive correlation between root diameter and harvest index, as well as root yield and the weight of the aboveground part of the plant. The results show that the cultivation of the plant by placing the cuttings in the vertical position had superior performance in relation to planting them in the horizontal position in regards to the root length and diameter, but there was no difference in the root productivity when considering the planting positions of the roots.