Antimicrobial drug resistance is one of the major threats due to the wide usage of broad-spectrum antimicrobial drugs in the general population. The present study was undertaken to investigate the antibacterial potential of Alternanthera philoxeroides methanolic extract (APME) against multidrug-resistant UTI pathogens. The preliminary phytochemical screening of the extract showed the presence of carbohydrates, amino acids, proteins, alkaloids, glycosides, steroids, flavonoids, tannins, and phenolic compounds. The quantitative estimation of total phenolic, tannin, and flavonoid contents was determined for the crude extract of APME through standard curves of gallic acid and rutin. The phenolic content of APME was found to be 12.4 mg of gallic acid equivalent (GAE)/g of extract. The tannin content was found to be 5.6 mg of GAE/g of extract, whereas the flavonoid content was found to be 3.2 mg of rutin/g of extract. The antibacterial potential of the extract was observed as maximum against Staphylococcus saprophyticus, moderate against Escherichia coli and Proteus vu/garis, and minimum against Proteus mirabilis. The minimum inhibitory concentration was ranged from 12.5 to 25 mg/ml. The Alternanthera philoxeroides were found to contain some bioactive compounds with pronounced antibacterial activity, therefore further phytochemical studies and their characterization should be needed to isolate the active constituents and evaluate the antimicrobial activities against a wide range of microbial pathogens.