The inappropriate usage of antibiotic is one of the factors of the emergence of the antibiotic resistance bacteria that limit the effectiveness of the current antibiotic and lead to the treatment failure. The combination of plant extract with antibiotic approach may lead to the new ways in the treatment of the infectious diseases and this combination may reduce of bacterial resistance toward antibiotics. The objective of this study was to determine the synergistic effect of Alocasia longiloba fruit extract with Ampicillin and Tetracycline against Staphylococcus aureus and Escherichia coli. The synergistic effect of A. longiloba fruit extract and antibiotics was determined by using agar well diffusion and minimal inhibitory concentration (MIC) Resazurin 96-well micro-dilution methods. The results of this study showed the increasing in the inhibition zone when the plant extract was combined with Ampicillin against E. coli. The value of MIC only showed by Ampicillin on E. coli which was 12.5 μg/ml, and the combination of plant extract and Ampicillin (2000 + 12.5 μg/ml). These results indicated that the fruit extract of A. longiloba showed low antibacterial activity against E. coli and S. aureus and this plant extract may show the inhibition if the concentration is increase and test against the different microorganisms.