Introduction: Jasminum officinale L. is a very important medicinal and industrial flowering aromatic plant. Methods: The present study deals with Jasminum officinale L. leaves extract (JOLE) as a reducing and capping agent for the synthesis of silver nanoparticles (AgNPs) by the green pathway. Phenolic profile of the extract was evaluated using HPLC-PDA/MS/MS technique. Jasminum officinale L. leaves extract silver nanoparticles (JOLE-AgNPs) were characterized by ultraviolet light (UV), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), zeta potential and X-ray diffraction (XRD). JOLE-AgNPs were examined for their cytotoxic activities by neutral red uptake assay (NRU) against bladder (5637) and breast cancer (MCF-7) cell lines. Results: HPLC-PDA/MS/MS tentatively identified 51 compounds of different chemical classes. UV spectra showed absorption peak at [lambda]max = 363 nm. The biosynthesized AgNPs were predominantly spherical in shape with an average size of 9.22 nm by TEM. The face cubic center (fcc) nature of silver nanoparticles was proved by XRD diffractogram. JOLE-AgNPs exhibited high cytotoxic activity against 5637 and MCF-7 cell lines compared to the cytotoxic activities of JOLE with [IC.sub.50] of 13.09 [micro]g/mL and 9.3 [micro]g/mL, respectively. Discussion: The silver nanoparticles formed by Jasminum officinale L. showed high cytotoxic activities against MCF-7 and 5637 cell lines and can be introduced as a new alternative cytotoxic medication. Keywords: silver nanoparticles, HPLC-PDA/MS/MS, cytotoxic, Jasminum, bladder cancer, breast cancer