This is the first time the bimetallic Ag-Mn nanoparticles - (Ag-Mn)NPs were synthesized using Arachis pintoia extract. The obtained samples were characterized and analyzed by various techniques, including X-Ray Diffraction, TEM, and FT-IR. XRD analysis confirmed the crystalline nature of nanoparticles. TEM images showed that the samples were nearly spherical in shape and uniform in size distribution with the average nanosizes of 3.3 nm for bimetallic (Ag-Mn)NPs, and 11.8 nm for monometallic AgNPs. FT-IR confirmed that flavonoids, phenolic acids, and alkaloid molecules can be bound to NPs acted both as the reducing and stabilizing agents. The results suggested that (Ag-Mn)NPs showed much greater potential against bacteria than that of AgNPs.