The synthesis of sliver nanoparticles (AgNPs) by green chemistry technique using the extract of mango leaf was performed. The study showed that the optimum time for AgNP synthesis is six hrs at a temperature of 60 °C, pH = 6.50 and AgNO₃ concentration = 10^-3 M. X-ray powder diffraction (XRD) study reveals that the AgNPs are crystalline with an average crystalline size of 15.55 nm while the transmission electron microscopy (TEM) image shows that they have a narrow size distribution and are rectangular rod shaped with weak agglomeration. The antimicrobial activity of the as-prepared AgNPs was tested against representatives of Gram-positive bacteria (Streptococcus pyogenes and Staphylococcus epidermidis) and Gram-negative bacteria (Proteus vulgaris and Klebsiella pneumonia); the results suggest that they have high activity against the tested organisms compared to levofloxacin, taken as a standard drug. Their cytotoxic activities were also tested against Human ovarian cancer (A2780) cell line and compared to that of Gemcitabine (GEM) as a standard drug where it was found that AgNPs significantly inhibited the viability and proliferation of A2780 thyroid cancer cells. Our data suggest that GEM and AgNPs exhibit potent apoptotic activity in human ovarian cancer cells. Combined treatment with GEM and AgNPs may show a significantly higher cytotoxic effect in ovarian cancer cells compared to that induced by either of these agents alone.