Dysentery is diarrhea disease with liquid bladder and spotting blood that caused by bacteria infection. The height of incidence of this disease in Indonesia was caused by genus Shigella. Indonesia used many plants as traditional medicine. One the medical plants, that is often used is mahagoni seeds (Swietenia mahagoni fructus). This study was conducted to determine activity of anti-bacteria of mahagoni seeds extract toward bacteria Shigella sp. Extraction of this research is done by using infuses method and percolation method with a solvent of water and ethanol. The extract obtained is made into variation of concentration which will be used as sample for next test of antibacteria activity. The test of anti-bacteria activity in this research was researched by using Kirby-Bauer method or disk diffusion. The identification of secondary metabolite compound that are suspected to have activity of anti-bacteria done quantitatively by using phytochemical analysis test. The results of identification antibacterial compound shows that there are positive contain alkaloids and saponins in all water extracts and ethanol extracts. The result of antibacterial activity shows that on the water extract by infundation and percolation method does not show inhibition zone or clear zone, while in ethanol extracts that used percolation method at concentration 25%, 50%, 75% and 100% proved if there are anti-bacteria activity toward Shigella sp. that showed inhibition zone or clear zone in agar plate. Minimal concentration of ethanol extracts that can inhibit the growth of bacteria is 25% with 5,6 mm diameter and 100% concentration have high inhibition zone with 8,9 mm diameter. Based on zone classification of inhibition zone activity, ethanol extracts mahagoni seeds included in the category of weak in inhibiting the growth of bacteria.