Background: Hepatitis B virus (HBV) infection is a public health issue worldwide. In Cameroon, its seroprevalence was 11.2% in 2018. However, data specific to cancer patients is missing and the risk of reactivation of viral hepatitis B in patients treated for cancer is not negligible. The objective of this study was to determine the seroepidemiological profile of markers of viral hepatitis B infection in cancer patients at the Yaounde General Hospital (HGY). Materials and methods: This cross-sectional study was conducted from March 2018 to December 2018. Total of 244 cancer patients was recruited from the HGY Oncology Department. Hepatitis B viral markers (HBs Antigen, HBe, and HBc Antibody, Anti-HBs, Anti-HBe) were determined by immunochromatographic assay (OnSite HBV-5 rapid test) in serum samples of patients. Results: Total 28 men (11.48%) and 216 women (88.52%) were recruited. The average age was 44.07 ± 1.57 years old. The majority of patients had breast cancer (77.05%), 24/244 patients had HBsAg positive (9.84%), 32/244 anti-HBc positive (13.11%), 32/244 anti-HBe positive (13.11%) and 64/244 anti- HBs positive (26.23%), 4/244 patients had acute hepatitis (1.64%), 20/244 patients were inactive carriers (8.20%), 20/244 were cured (8.20%), 48/244 were immunized by vaccination (19.67%) and 152/244 were free from hepatitis B (62.30%). Conclusion: HBV testing should be performed in patients scheduled for cancer chemotherapy and those tested negative should be advised to join the vaccination programme. About 8.2% of patients are at a risk for reactivation of hepatitis when receiving chemotherapy.