We distributed a questionnaire to 209 patients who visited the Digestive Disease Center of Kurume University for liver disease treatment from October 2006 to April 2007 to determine whether patients with hepatitis C virus (HCV) or hepatitis B virus (HBV) disclosed their disease status to dental clinics personnel. We found that 59.8% (125/209) always did so, 12.0% (25/209) sometimes did so, and 28.2% (59/209) never did so. The main reason (71.2%) for nondisclosure was failure of dental healthcare workers to ask whether patients had systemic disease. Other reasons included fear of negative reactions from healthcare workers (11.9%) and not wanting dentists or staff to know their specific liver ailment (10.2%). Men were less likely than women to disclose status for these reasons. It thus cannot be over emphasized that liver disease patients be advised by medical specialists to make known their HCV or HBV status when undergoing dental care. Above all, it is important for dental workers to take standard precautions with all patients to ensure medical safety and to prevent infection in dental practice. The government should take appropriate measures to encourage and support dentists who use precautions to prevent nosocomial infection.