The antibacterial activity of the various extracts of the stem bark of Prosopis cineraria (Linn.) Druce, was evaluated by the agar well diffusion method. The extracts were prepared by continuous hot percolation method with chloroform and methanol. Aqueous extract was prepared by maceration. The presence of phytosterols, flavonoids, tannins, phenols, carbohydrates, proteins and aminoacids were detected in the preliminary phytochemical tests. Moderate antibacterial activity was observed in the extracts (250μg/ml) against some pathogenic microorganisms when compared with the standard ciprofloxacin.