Abstract One in seven men in the United States will be diagnosed with prostate cancer in his life time, in part because of the prevalence of screening for serum levels of prostate specific antigen (PSA). However, this has led to the overtreatment of the disease, leading to recommendations against frequent PSA testing and establishing the need for a more informative biomarker in prostate cancer. Circulating tumor cells (CTCs) are rare cells present in the blood stream of cancer patients at the low frequency on the order of one CTC in one billion normal blood cells. The graphene oxide chip (GO Chip) is a microfluidic CTC capture device with increased sensitivity and purity due to its use of the nanomaterial graphene oxide to present a capture antibody against the epithelial cellular adhesion molecule (EpCAM). In this study, whole blood was collected from 50 prostate cancer patients, including those with metastatic, localized, castrate resistant, and castrate sensitive disease, and analyzed using the GO Chip. Captured cells were stained for cytokeratin, CD45, and DAPI, with nucleated cytokeratin positive cells being denoted as CTCs. CTCs were detected in 47 out of 50 patients, and an average of 5.94 CTCs/mL was recovered from each sample. Correlation of CTCs with surrogate endpoints could improve the utility of CTCs as a liquid biopsy, potentially advancing their application in translational research. Citation Format: Molly Kozminsky, Hyeun Joong Yoon, Nallasivam Palanisamy, Kathleen Cooney, Maha Hussain, Ajjai Alva, Todd Morgan, Sunitha Nagrath. Application of a graphene oxide based microfluidic device (GO Chip) to prostate cancer circulating tumor cell capture and analysis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1585. doi:10.1158/1538-7445.AM2015-1585