Hepatitis E virus infection is usually a self-limited disease. However, during the last years there has been growing evidence for prolonged and chronic infection occurring in patients with immunosuppression. Also patients with malignant and rheumatic diseases have been identified to be at risk for chronic hepatitis E. However, their course and prognosis are not well characterized and there have been no reports of hepatitis E virus infection in patients with gynecological cancer. Here, we report three Caucasian females with breast and ovarian cancers presenting with elevation of aminotransferase levels during anticancer treatment. Although only few or no clinical hints suggested hepatitis E virus infection, the diagnosis of hepatitis E virus infection was confirmed by seroconversion, which might occur with some delay, and/or by polymerase chain reaction. While two patients had a self-limited course, the third patient with a high-risk oncological constellation required ribavirin in order to resume chemotherapy. These cases highlight the need for hepatitis E virus testing in patients with gynecological cancer and elevated aminotransferase levels. Further, these cases show that in selected high-risk patients, ribavirin treatment may be necessary based on the decision of a multidisciplinary team.