Although 10% of the Yaounde population are hepatitis B surface antigen (HBsAg) positive, nothing is known about hepatitis D virus (HDV) infection in them. Sera from 110 HBsAg subjects were tested for HDV infection (antibody and antigen). The subjects were 43 pregnant women, 23 prostitutes, 20 patients with febrile jaundice, 16 multitransfused sickle cell children and 8 medical students. Thirty of the 110 (27.3%) had antibodies to the HDV (HDV-Ab). Two of 91 tested for HDV antigen (2.2%) were positive. The highest HDV-Ab prevalence (62.5%) was obtained from sickle cell children (10/16). Thus, HDV infection was found in about one fifth to one third of the HBsAg-positive subjects we studied and the main route of transmission appears to be by blood transfusion.