Hepatitis B virus (HBV) infection is a major public health problem in the world. In Congo, studies on the prevalence of HBV infection are common but HDV infection is rare. Objective: Contribute to improve the management and prevention of HBV and HDV infections. Patients and Methods: This was a descriptive and cross-sectional study conducted from January to August 2016 in the health services of the various departments of Congo and at the national public health laboratory in Brazzaville. All patients with HBsAg surface antigen who were at least 18 years old and who consented to the study were included. The HBs antigen was first tested by a rapid test then confirmed by ELISA. All HBsAg positive patients were subsequently subjected to a second ELISA test for Delta antibody. The techniques of extraction and conventional and specific gene amplification were carried out on plasma for the identification of the genotypes of the two viruses. The data analysis was done with EpiInfo V7 software. The proportions were compared using the Chi-square test or the Fisher test at the significance level of 5%. Results: 1618 subjects were included, of whom 180 were positive for HBsAg, a frequency of 11.12%. The sex ratio (M/F) was 0.77%, the mean age was 40.2 ± 15.6 years with extremes ranging from 18 to 88 years. Of the 180 HBsAg positive, 22 were anti-VHD positive, a frequency of 12.22%. HBV DNA was amplified in 83.8% (151/180), HDV RNA in 63.6% (14/22). For HBV, three genotypes were identified: E (46.9%), A (43.7%) and D (9.4%), however for VHD three genotypes D1, D5, D8 were identified. Conclusion: Co-infection of hepatitis