The cross-immunity between tuberculosis and leprosy is unknown. The aim of this pilot study was to evaluate the occurrence of Mycobacterium tuberculosis and M. leprae infection in Marshallese adult volunteers in Springdale, Arkansas, U.S.A., a population that experiences high rates of leprosy and tuberculosis. We used immunodiagnostic testing for tuberculosis and leprosy infection and found significant prevalence of latent tuberculosis infection (19.0%), and asymptomatic Mycobacterium leprae infection (22.2%). We found a negative association between presence of antibodies to Mycobacterium leprae and a positive interferon-γ release assay for Mycobacterium tuberculosis infection, prevalence odds ratio = 0.1 (95% CI = 0.0, 0.9). Although these findings require confirmation on a larger scale, they are supportive of the existence of cross-immunity.