with the aim of studyng the hay made from the upper third of cassava foliage in development of growing rabbits, 32 rabbits, 16 males and 16 females, breed white new zealand from 50 to 70 days of age were used. the rabbits were distributed in block randomized design within sex, with 4 treatments (4 levels of inclusion the cassava foliage hay 0, 10, 20 and 30%) with eight animals in each block and 2 replicates in each block, being each replicate constituted of one animal per experimental unit. the weight at 70 days of age decresead linearly (p<0.05) when the level of cassava foliage hay was increasead in diets. the other characteristics of performance and carcass were not affected with the cassava foliage hay inclusion levels. the results have showed that the levels of cassava foliage hay is viable not more than 20% of inclusion in diet.