Chronic hepatitis B virus (HBV) infection is a major health problem in sub-Saharan Africa, where prevalence is > or =8%, and is increasingly seen in African immigrants to developed countries. A retrospective audit of the medical records of 383 immigrants from sub-Saharan Africa attending the infectious diseases clinics at the Royal Melbourne Hospital was performed from 2003 to 2006. The HBV, human immunodeficiency virus (HIV) and hepatitis C virus (HCV) serological results are reported, with a focus on the isolated core antibody HBV pattern (detection of anti-HBc without detection of HBsAg or anti-HBs). Two-thirds (118/174, 68%) of those tested had evidence of HBV infection with detectable anti-HBc. Chronic HBV infection (serum HBsAg detected) was identified in 38/174 (22%) and resolved HBV infection (both serum anti-HBs and anti-HBc detected) in 45/174 (26%). The isolated core antibody pattern was identified in 35/174 (20%), of whom only 1/35 (3%) had detectable serum HBV DNA on PCR testing, indicating occult chronic HBV (OCHB). Only 8/56 (14%) patients with negative anti-HBc had serological evidence of vaccination (serum anti-HBs detected). HIV infection was detected in 26/223 (12%). HCV antibodies were detected in 10/241 (4%), of whom 8 (80%) had detectable HCV RNA. Viral co-infection was detected in only 2/131 (1.5%) patients tested for all three viruses. The isolated core antibody HBV pattern was common among sub-Saharan African patients in our study. These patients require assessment for OCHB infection and monitoring for complications of HBV.