Background: Nanoparticles have attracted significant attention from researchers due to their intriguing properties, such as size and shape-dependent optical, antimicrobial, and electrical characteristics. Several different preparation techniques have been used to synthesize nanoparticles, including laser ablation, gamma irradiation, electron irradiation, chemical reduction, photochemical methods, microwave processing, and biological synthetic methods. Objective: As part of our research, we conducted experiments involving the extraction of silver nanoparticles from eggshell powder and explored their potential biological applications. Methodology: The synthesis of silver nanoparticles (AgNPs) from eggshell was analyzed using UV-visible spectroscopy, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The antibacterial activity and anticancer potential of the AgNPs were determined using MTT assay against MCF-7 breast cancer cell lines. Results: The UV-visible analysis detected a peak at 480 nm, indicating the crystalline structure of the nanoparticles that were synthesized biologically. These nanoparticles have an average size of approximately 41.68 nm and exhibit a spherical shape. The synthesized silver nanoparticles exhibited strong antibacterial activity against multidrug-resistant clinical bacterial isolates, including Gram-positive bacteria such as Staphylococcus hominis and Streptococcus mutans , and Gram-negative bacteria such as Klebsiella pneumoniae and Escherichia coli , which are commonly associated with nosocomial infections. Through the utilization of the disc diffusion approach. The activity seen can be ascribed to the distinctive biological and physicochemical characteristics of the AgNPs, which aid in the rupture of bacterial cell membranes. The MCF-7 cell line exhibited the highest decrease when exposed to a concentration of 400 µg/mL of AgNPs. The results underline the potential of eggshell extract as an environmentally friendly and effective biological agent for synthesizing AgNPs with strong antibacterial and anticancer activities. Conclusion: AgNPs can be synthesized utilizing eggshell in an environmentally benign manner, and these AgNPs can serve as a cost-effective antibacterial and anticancer agent.