AIM: To determine the possible routes of intrafamilial transmission pattern in pediatrie cases of chronic hepatitis B virus (HBV) infection. METHODS: In this descriptive retrospective study, 302 children with chronic HBV infection from 251 families and their parents attending the Social Security Children’s Hospital and Doctor Sami Ulus Children’s Hopsital in Ankara between December 1998 and May 2000, were enrolled in. Screenings and diagnosis of chronic HBV infections were established according to the Consensus 2000. RESULTS: In the studied 302 children with chronic HBV infection, mothers of 38% and fathers of 23% were HBsAg positive. The HBsAg positivity in at least two siblings of the same family was 61% when both parents were HBsAg positive. CONCLUSION: It is well known that hon’zontal transmission is quite common in countries where Hepatitis B Virus is moderately endemic. To our best knowledge, this is the largest series observed regarding the horizontal transmission in pediatrie chronic HBV infection in Turkey. It is necessary to expand the preventive programs to target not only the newborn period but also all stages of childhood. AIM: To determine the possible routes of intrafamilial transmission pattern in pediatrie cases of chronic hepatitis B virus (HBV) infection. METHODS: In this descriptive retrospective study, 302 children with chronic HBV infection from 251 families and their parents attending the Social Security Children’s Hospital and Doctor Sami Ulus Children’s Hopsital in Ankara between December 1998 and May 2000, were enrolled in. Screenings and diagnosis of chronic HBV infections were established according to the Consensus 2000. RESULTS: In the studied 302 children with chronic HBV infection, mothers of 38% and the fathers of 23% were HBsAg positive. The HBsAg positivity in at least two siblings of the same family was 61% when both parents were HBsAg positive. CONCLUSION: It is well known that hon’zontal transmission is quite common in countries where Hepatitis B To our best knowledge, this is the largest series observed regarding the horizontal transmission in pediatrie c hronic HBV infection in Turkey. It is necessary to expand the preventive programs to target not only the newborn period but also all stages of childhood.