A national surveillance system for chronic hepatitis B was established in 2008, in collaboration with reference centers (university hospital hepatology departments), to describe the epidemiological and clinical-biological characteristics of patients newly diagnosed with chronic hepatitis B. Chronic hepatitis B is defined as HBs antigen (HBsAg) carriage for more than six months. The patient characteristics collected include the circumstances of HBsAg detection and their risk exposures to the hepatitis B virus (HBV). We present certain characteristics of patients who have not previously received antiviral treatment, according to the level of HBsAg prevalence in their country of birth (low vs. moderate/high endemicity). Between January 2008 and August 2009, 1,016 patients were treated, 78% of whom were born in an area of moderate or high HBV endemicity. HBsAg detection was incidental in 69% of patients. The time interval between screening and treatment initiation, determined for 837 patients, exceeded three years for 41% of patients born in areas of low HBV endemicity and for 22% of those born elsewhere. These preliminary results suggest suboptimal HBsAg screening practices and delays in the management of screened individuals, particularly those born in areas of low HBV endemicity. (R.A.)