Abstract: Medicago sativa (alfalfa) was used to make silage, with and without addition of additives. Alfalfa plants were freshly harvested at the initial blooming stage, when their dry matter content was about 400 g·kg^-1 (fresh matter basis). The effects of additives and ensiling density on the quality of alfalfa silage were investigated in an experiment with eighteen treatment levels. The quality of silages was analyzed after 45 days of fermentation. The results showed that silage treated with S (sucrose), S+LP (sucrose+Lactobacillus. plantarum) and S+LC (sucrose+Lactobacillus. casei) had lower pH, butyric acid content, NDF neutral detergent fiber content, and acid detergent fiber content than silages without these additives. Treatments with CE (acremonium cellulose), LP+CE, and LC+CE did not significantly improve the quality of silage. Treatments with additives resulted in higher quality alfalfa silage than treatments without additives (P<0.05). Preparing silage with higher density did not significantly improve its quality but significantly increased its DM (dry matter) content and ammonia nitrogen/total nitrogen ratio (P<0.05). The additive×density interaction was not a significant factor for silage quality (P>0.05).