Tulsi plant, Ocimum sanctum L., is famous for its therapeutic potentiality. The present study investigates the antibacterial activity of O. sanctum leaf extracts, and the bioactive components present in the extracts. The antibacterial activity of ethanolic leaf extract of O. sanctum: dark variety; Krishna tulsi (DOSE) and bright variety; Rama tulsi (BOSE), and aqueous leaf extract of dark variety (AqDOS) and bright variety (AqBOS) of O. sanctum was determined by in vitro methods against gram-negative and gram-positive clinical bacterial isolates. Phytochemical screening of the extracts was done qualitatively, and thin layer chromatography (TLC) was performed using n-hexane-ethyl acetate mobile phase. The ethanolic extracts showed more antibacterial activity as compared to aqueous extracts in terms of ZDI (zone diameter of inhibition); the ZDI of DOSE ranged 20 -28 mm for gram-positive, and 14 -23 mm for gram-negative bacteria, whereas in case of BOSE the ZDIs ranged 11 -22 mm and 12 -18 mm, respectively, for gram-positive and gram-negative bacteria. The Rf values of phytocomponents detected on the TLC plate, ranged 0.06 -0.94. The O. sanctum leaf extracts had broad spectrum antibacterial activity and found rich source of phytochemicals, which thus, be utilized against a broad range of bacterial infection.