Infection with human immunodeficiency virus (HIV) is associated with substantially increased incidence of non-Hodgkin lymphoma (NHL). This risk may be driven, in part, by reduced immune control over viral infections in the setting of acquired immunodeficiency syndrome (AIDS), although the lymphomagenic mechanisms are not yet established. We used bead-based multiplex assays to measure antibody seroreactivity to 32 viral antigens representing 22 different viral infections (human herpesviruses 1-8, hepatitis B and C virus, human T-lymphotropic virus type-1, and human polyomaviruses) in two prospective HIV cohorts. Incident (n = 28) and prevalent (n = 38) AIDS-related NHL cases were matched by age, sex, race, and CD4 count to 67 HIV-positive control individuals without AIDS-NHL. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations of AIDS-NHL with the number of different viruses to which an individual was seropositive and seroreactivity to individual antigens. Seropositivity to an increasing number of viruses was inversely associated with AIDS-NHL (OR per virus = 0.84, 95% CI = 0.72-0.98). Seroreactivity to herpes simplex virus 2 2mgG unique antigen (OR = 0.47; 95% CI = 0.23-0.97) and to WU polyomavirus viral capsid protein (OR = 0.26, 95% CI = 0.10-0.65) was significantly lower in AIDS-NHL cases compared to controls. In this evaluation of antibodies to multiple viruses, we observed an inverse association between seropositivity to a larger number of viruses and AIDS-NHL. While in need of further evaluation, our data raise the novel hypothesis that insufficient exposures or impaired humoral immune responses to viral infections may be associated with AIDS-related lymphomagenesis.