Various species of Alhagi are known for a wide diversity of ethnopharmacological uses. This study explored the in vitro antimicrobial and cytotoxic potentials of the crude ethanolic extract and isolated fractions from the traditional Saudi plant Alhagi graecorum. The antimicrobial activity was evaluated against 19 pathogenic microbial strains using the broth micro dilution assay. On the other hand, the cytotoxicity was assessed using the crystal violet staining method on MCF-7, HepG-2, HCT-116, A-549, and HEp-2human cell lines. Results showed that the highest antimicrobial activity was shown by the ethyl acetate extract, followed by the dichloromethane and total alcohol extracts. The aqueous extract had no effect on any of the tested microorganisms at 20mg/ml. In addition, the ethyl acetate extract displayed remarkable cytotoxic activity on all five human cell lines with IC50 values ranging from 2.7 to 8.23 μg/mL, followed by the dichloromethane extract with IC(50) values between 9.4 and 19.7μg/mL using doxorubicin as a reference drug.