Two field experiments were conducted during 2001/2002 and 2002/2003 seasons at Kaha Experimental Station, Vegetable Research Department, Kalubia Governorate in order to study the effects of nitrobein biofertilizer, nitrogen levels and their interactions on plant growth, yield and its components as well as chemical composition of garlic plants cv. Sids 40 (Allium sativum, L. ). Seven kilograms of nitrobein (a biofertilizer produced by the Egyptian Ministry of Agriculture, containing active bacteria capable to N₂-fixing) was tested with three levels of nitrogen i.e., 50,100 and  150 kg./fed. in a split plot design. Biofertilizer nitrobein occupied the main plots, while, the nitrogen levels represented the sub-plots. Data showed that, plant height, neck and bulb diameter, as well as fresh and dry weight of leaves and bulb were increased significantly by using nitrobein biofertilizer. Both, total yield (ton/fed.), plant fresh weight (gm.), and  clove  weight (gm.) were increased significantly with nitrobein compared with the control. Nitrogen, phosphorus and potassium uptake, as well as nitrogen and dry matter percentages were higher in garlic plants that received nitrobein. Concerning nitrogen levels, both (100 and 150 kg./fed.) treatments increased significantly plant height, neck and bulb diameters, as well  as fresh and dry weights  of leaves and bulb. No significant interactions were observed between the nitrogen levels and nitrobein biofertilizer on the mineral uptake of N, P and K and the mineral concentration in garlic bulbs and bulbs dry matter as well.