Essential oil is one of the natural compounds from plant extract that has the potential as a natural antibacterial for inhibiting the hydrolysis of urea compound into ammonia gas in livestock wastes. This research aims to measure antibacterial effects of Maja Fruits Extract (MFE) on Escherichia coli and its potential as a urease inhibitor in excreta medium. MFE was extracted using Maceration method. The results indicated that antibacterial activity of MFE was low or resistant, with the biggest diameter of inhibition zone occurred on agar medium was 14.26 ± 0.75 mm. The antibacterial ability of MFE with an addition of 3% (v/v) in liquid medium gave the lowest graph of bacterial growth. MFE has the potential as an antibacterial and urease inhibitor compound, which could be applied to inhibit the hydrolysis of urea by microorganisms so that it can reduce the emission of ammonia gas from livestock wastes, especially chicken excreta.