Over recent years, metal nanoparticles have largely been investigated due to their potential activities. This study focused on synthesizing silver nanoparticles (AgNPs) using the desert plant Cyperus conglomeratus, which is the most abundant species on the sand dunes in the UAE, and their anticancer activity. The synthesized AgNPs were characterized using UV-visible spectra, X-ray diffraction, energy dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, dynamic light scattering, and scanning electron microscope. The results showed that the AgNPs are monodispersed and mostly spherical in shape. The cytotoxicity effects were investigated against breast cancer cells MCF-7 and normal fibroblast using MTT assay which showed selective cytotoxicity against MCF-7 with an IC50 at 5 μg/mL but not fibroblast. Moreover, the apoptotic effects were confirmed using annexin V-FITC-PI double staining kit and real-time PCR for apoptotic genes. Therefore, our results revealed potential anticancer applications of the C. conglomeratus biosynthesized silver nanoparticles.