Garlic (Allium sativum) is a important plant used in diet and in siddha medicines. Allium species are used in traditional medicine for centuries. The present study aimed at assessing the preliminary phytochemical analysis and antibacterial activity of garlic by disc diffusion method against ten MTCC bacterial species. Various solvent extracts of garlic inhibited the growth of bacterial species at the concentrations of 100, 200, 300, 400 and 500μg. All the four extracts showed maximum activity against Staphylococcus aureus. Among the solvent extracts, methanol extract of garlic showed better result in antimicrobial activity. This may be due to the extraction of all the major phytochemicals such as flavonoids, phenolics, saponin, alkaloids and tannins in methanol. The extracts showed concentration dependent antibacterial activity against bacterial cultures. The traditional use of Allium species for infectious diseases and for controlling bacterial infection appears to be justified.