The production of silage provides the opportunity to preserve roughage for subsequent use as a ruminant feed during times of inadequate pasture growth. This study evaluated growth, intake and feed efficiency in hair sheep lambs fed sorghum silage, grown in monoculture · or in association with legumes, as a roughage source. For the trial 12 mixed-sex lambs were assigned, stratified by gender, to diets based on sorghum silage grown in monoculture (SM) or in association with Leucaena leucocephala (LA) or Desmallthus virgatus (DA). Diets were replicated in two pens, with two animals per pen. Silage (7.5% of body weight as fed) was supplemented with coconut meal (0.5 % of body weight) and molasses (1.0% of body weight). Dry matter content of SM (27.7 %) was slightly lower than those of LA and DA (29.2%), but the pH was similar for all silage types (4.1). The pre-ensiling dry matter legume content was 13.3 % for LA and 12.0% for DA. Animals were on trial for a 24-day period, following a 4-day adjustment period when roughage pooled across silage types was fed. The average lamb age and body weight at the beginning of the trial were 122.5±2.3 days and 15.7±0.4kg. Average daily gain differed among diets (P<0.05), SM being lowest (43±5 g/day), DA highest (90±18g/day) and LA intennediate (66±5 g/day). Total intake was not significantly different among diets, ranging from 457±38 g dry matter/day for SM to 532±35 and 537±24 g dry matter/day or LA and DA. Roughage intake was also not significantly different between silage types and ranged from 384±13 g dry matter/ day for SM to 333±36 and 332±25 g dry matter/day for LA and DA. The gain to feed ratio was significantly (P<0.05) higher in animals on DA (0.167 ± 0.02) than on SM (0.094 ± 0.02), LA (0.125 ± 0.02) being intermediate. The results from this trial would indicate a more favorable animal response to diets based on silage derived from grass/legume associations.