Although hepatitis C virus (HCV) infection has been shown to be associated with development of non-Hodgkin’s lymphoma (NHL), few studies have investigated the association between chronic HBV infection and NHL. The purpose of this study was to compare the incidence of NHL between patients with and without chronic hepatitis B virus (HBV) infection. Using automated laboratory result and clinical data from two United States health systems, we identified individuals with chronic HBV infection from January 1, 1995 through December 31, 2001. Using each health system’s population-based tumor registry, we identified all cases of NHL diagnosed through December 31, 2002. We excluded any individual with a history of NHL or human immunodeficiency virus (HIV). We fit Cox proportional hazards models to calculate hazard ratios comparing the incidence of NHL between chronic HBV-infected patients (N = 3,888) and patients without HBV (N = 205,203) drawn from the source populations. We identified 8 NHL cases in the chronic HBV infection cohort and 111 cases in the comparison cohort. Patients with chronic HBV infection were 2.8 times more likely to develop NHL than matched comparison patients (adjusted hazard ratio = 2.80, 95% confidence interval = 1.16-6.75), after controlling for age, race, sex, income, Charlson comorbidity index, study site, and HCV infection. CONCLUSION: chronic HBV-infected patients were nearly 3 times more likely to develop NHL than comparison patients.