BACKGROUND/AIMS: The aims of the present study were to determine the outcomes of inactive hepatitis B virus (HBV) surface antigen (HBsAg) carriers over a 10-year study period and to elucidate the HBV serological profile of their family members. METHODS: We retrospectively analyzed the medical files of inactive HBsAg carriers followed up at the Department of Infectious Diseases of Kocatepe University Medical Faculty Hospital between March 2001 and January 2011. RESULTS: In total, 438 inactive HBsAg carriers were enrolled in this trial. The follow-up period was 33.7+/-22.5 months (mean+/-SD). Anti-hepatitis-B surface antibody seroconversion occurred in 0.7% of cases, while chronic hepatitis B was found in 0.5%. The anti-hepatitis-D virus (HDV) status was evaluated in 400 patients and anti-hepatitis C virus (HCV) in 430. It was found that 1% and 0.2% were positive for anti-HDV and anti-HCV, respectively. HBV serology was investigated in at least 1 family member of 334/438 (76.3%) patients. The HBsAg positivity rate was 34.6% in 625 family members of 334 patients. A comparison of the HBsAg positivity rates in terms of HBV DNA levels in index cases revealed that HBsAg seropositivity rates were higher in family members of HBV DNA-negative patients than in family members of HBV DNA-positive cases (P=0.0001). CONCLUSIONS: The HBsAg positivity rate was higher in family members of inactive HBsAg carriers than in the general population; these family members therefore have a higher risk of HBV transmission. Furthermore, despite negative HBV DNA levels, transmission risk was not reduced in these patients, and horizontal transmission seems to be independent of the HBV DNA value.