Alfalfa (Medicago sativa) presents a substantial part of livestock diets because of its high protein content. However ensiling of alfalfa is difficult due to its high buffering capacity and low content of water-soluble carbohydrates (WSC). The addition of silage additives thus would exerts a positive effect on the fermentation process. Lactic acid bacteria (LAB) are distributed at different quantities throughout the environment. They ferment soluble sugars and produce lactic acid from water-soluble carbohydrates as the main fermenta­tion end-product. Lactic acid is the primary acid responsible for a decrease in the pH of silage. Although it is well recognized that epiphytic LAB have an important role in silage fermentation, their numbers in the standing crop are limited and variable (Muck 1990; Lin et al. 1992). The objectives of the study were to evaluate the effects of wilting and additives on the number LAB in alfalfa forage and silage.