High grade serous ovarian carcinomas account for nearly 70% of ovarian malignancies. They are characterized by high initial chemosensitivity to platinum based therapies, however 75% of patients relapse after treatment and subsequently become chemotherapy resistant . The development of more effective molecularly targeted therapies to improve survival is urgently required. In this study we show that 1) KRT5 and KRT6C are expressed by ovarian cancer cell lines, 2) KRT5 expression levels predict reduced PFS and OS for serous ovarian cancer patients, 3) KRT6 expression levels predict reduced PFS but not OS for serous ovarian cancer patients, 4) Both high K5/6 or high K5 positivity in serous ovarian cancers can predict reduced PFS but not OS, 5) K5/6 and K5 immunostaining is increased in serous ovarian cancers following neoadjuvant chemotherapy, 6) KRT5 expression levels but not KRT6C are increased in serous primary cells derived from patients’ ascites with chemoresistant disease and 7) K5 protein expression is increased in serous ovarian cancer cell lines following carboplatin treatment. Our findings indicate that K5 expression could be used to predict serous ovarian cancer prognosis and may be used to identify cancer cells that are resistant to chemotherapy.