Transtadial persistence and stercorarial shedding of hepatitis B virus (HBV) in common bed bugs, Cimex lectularius L., was studied by using experimental infectious blood feedings, infectious intrathoracic inoculations, and virus detection by polymerase chain reaction and Southern hybridization. Results showed that HBV persisted after an infectious blood meal in bed bug bodies for up to 35 d after the infectious blood meal. It was passed transtadially through one molt regardless of instar, was shed in fecal droplets for up to 35 d after the infectious blood meal, but was not passed transovarially. In bugs inoculated intrathoracically, HBV was detected for 21 d postinoculation. Previous studies detected the hepatitis B surface antigen found on both infectious and noninfectious particles in bed bugs. In this study, the presence of nucleic acids amplified from a conserved core region of the viral genome in bodies and feces of C. lectularius suggests that the HBV virus may be mechanically transmitted in feces or when bugs are crushed, during feeding.