Abstract Early detection of cancer can drastically increase the survival rate of the patient. While tremendous efforts were devoted to developing early detection tools, especially cancers in the peritoneal cavity such as ovarian cancer are often detected late after the exfoliated cancer cells have spread throughout the peritoneal cavity and have formed metastases, leading to a high mortality. However, early detection can increase the 5-year survival rate of afflicted women from less than 30% to more than 80%, highlighting the importance of developing early detection tools. Ideally, these tools should be specific for ovarian cancer but include most histological sub-types, and be non-invasive. An attractive source of biomarkers lies within the complex gut microbiome- whose membership and functionality are tightly associated with the health of its host. Changes to the gut microbiota, a concept referred to as dysbiosis, are associated with disease in humans. Here we describe changes in the intestinal microbiota as a function of the presence of ovarian cancer metastases in the peritoneal cavity. We postulate that these might serve as useful markers for earlier detection of ovarian cancer or other peritoneal-associated cancers. Citation Format: Eva M. Schmelz, Paul C. Roberts, Monica A. Ponder. Ovarian cancer-induced changes in the intestinal microbiota as potential biomarkers for early detection. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-155. doi:10.1158/1538-7445.AM2014-LB-155