Leucaena leucocephala leaves (LL) were ensiled by mixing with 20% rice bran and 20% water (fresh LL basis). The material was kept for 21, 51, 81 and 111 days in vacuumed double layer plastic bags, each containing 26 kg. Five bags were randomly taken at each interval for quality evaluation by organoleptic test as well as by organic acid and chemical analysis. It was found that the ensiling period did not have much influence on most of the chemical compositions. All samples of leucaena leaf silage (LLS) had pH of 4.4-4.5 and 35.22-35.65% DM (dry matter). The compositions on DM basis were 21.49-22.29% CP (crude protein), 7.76-8.22% EE (ether extract), 31.18-33.68% NDF (neutral detergent fiber), 2.0-2.9% acetate and 6.9-9.7% lactate (DM basis). DM loss was 10.35-12.32% which was in the normal range for good quality silage. The most interesting points were the increment of β-carotene after ensiling from 88.50 to 99.92-120.25 mg/kg DM while mimosine content decreased over 90% (from 1.79 to 0.12-0.16% of DM) which were superior to a drying method. It indicated that LLS is a good alternative for preserving LL and for reduction of mimosine.