This study was carried out to evaluate the antibacterial effectiveness of lemon juice, (ripe and unripe) extracts; using agar disc diffusion method. The test organisms (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillis subtilis were obtained from National Agency for Food, Drug Administration and Cotrol Agulu, Anambra State. A serially diluted 24 hours broth culture of the test organisms was used to inoculate Mullar Hinton agar; and 10mm diameter paper disc impregnated with test organisms lace in it before incubation. The result of the test showed that the ripe lemon juice inhibited Staphylococcus aureus (30mm), Pseudomonas aeruginosa (28mm), Bacillus subtilis (20mm) but no inhibition on Escherichia coli while unripe lemon juice inhibited Staphylococcus aureus (24mm), Pseudomonas aeruginosa. (30mm), Escherichia coli (23) but did not inhibit Bacillus subtilis.The MIC and MBC carried out using ripe lemon on Staphylococcus aureus gave 30%v/v for both; while unripe lemon recorded 30%v/v and 15%v/ MIC and MBC results respectively on Pseudomonas aeruginosa. The result of this work has shown that lemon juice (both ripe and unripe) can be used in the treatment of infections caused by these organisms. However, more specific researches are needed for full application in the pharmaceutical industry. Key Words: Lemon, Antibacterial, Inhibition.