Microbial nanoparticles are considered a major medical breakthrough with significant potential in disease diagnostics and therapy. These microorganism-derived nanoparticles leverage microbial and chemical versatility to create nanoscale particles with tailored properties. In cancer treatment, they enable advanced targeted drug delivery and immunomodulatory therapy, essential for therapeutic outcomes and reduced toxicity. A key advantage is their precise drug delivery to the cancerous tissues without disturbing healthy cells, minimizing off-target effects, a common drawback for conventional chemotherapy. Moreover, microbe-derived nanoparticles could be engineered to target-specific biomarkers like human epididymis protein 4, cancer antigen 125, folate receptor alpha, and human epidermal growth factor receptor 2 enhancing their effectiveness. It significantly contributes to cancer diagnostics through functionalization with imaging agents like iron oxide nanoparticles and fluorescent quantum dots to enable visualization and monitoring of tumors. Epithelial ovarian cancer is the fifth most common cause of gynecologic cancer deaths in women worldwide. Therefore, the current state of understanding of microbial synthesis and characterization of nanoparticles, the mechanisms thereof, and their potential role in ovarian cancer treatment are reviewed in the present work. By tackling challenges like biocompatibility and large-scale production, microbial nanoparticles can pioneer revolutionary advancements in oncology.