Background: Hepatitis B and C are the leading causes of liver diseases worldwide. For hematological and solid malignancy patients undergoing chemotherapy, increases in HBV DNA and HCV RNA levels can be detected which may result in reactivation and hepatitis-related morbidity and mortality. The aim of this study was to determine the seroprevalence of Hbs ag and Anti HCV positivity in patients with solid malignancies undergoing chemotherapy and consequences during follow-up. Materials and Methods: The files of 914 patients with solid malignancies whose hepatitis markers were determined serologically at diagnosis were reviewed retrospectively. All underwent adjuvant/palliative chemotherapy. For the cases with HBV and/or HCV positivity, HBV DNA and HCV RNA levels, liver function tests at diagnosis and during follow-up and the treatment modalities that were chosen were determined. Results: Of 914 cases, Hbs Ag, anti Hbs and anti HCV positivity were detected in 40 (4.4%), 336 (36.8%) and 26 (2.8%) of the cases respectively. All of the Hbs ag positive patients received prophylactic lamuvidine before the start of chemotherapy. In the Hbs ag and anti HCV positive cases, liver failure was not detected during chemotherapy and a delay in chemotherapy courses because of hepatitis was not encountered. Conclusions: Just as with hematological malignancies, screening for HBV and HCV should also be considered for patients with solid tumors undergoing chemotherapy. Prophylactic antiviral therapy for HBV reduces both the reactivation rates and HBV related mortality and morbidity. The clinical impact of HCV infection on patients undergoing chemotherapy is still not well characterized.