A commercial anti-dengue virus (DENV) indirect IgG enzyme-linked immunosorbent assay (ELISA) for serological diagnosis was evaluated for its utility in determining previous DENV exposure in US travelers. The Boston Area Travel Medicine Network clinics used Focus Diagnostics anti-DENV IgG ELISA to measure anti-DENV IgG antibodies in 591 pre-travel specimens from US residents who had traveled to dengue endemic countries. When using the manufacturer's index cut-off value for this ELISA, false-positive results were observed that overestimated the perceived past DENV exposure in US travelers. Validation of 121 of these anti-DENV IgG results by plaque reduction neutralization test (PRNT) was used for receiver operator characteristics (ROC) curve optimization of the index cut-off value from 1 to 3.0, improving the specificity of the anti-DENV IgG ELISA from 24% to 95.7%. Additionally, previous vaccination with yellow fever virus contributed to 52.8% of the false positive rate in the anti-DENV IgG ELISA results. Optimization of the cut-off value of the anti-DENV IgG ELISA provided better interpretation and confidence in the results and eliminated the need for confirmation by PRNT. The travel history of US travelers was also useful for categorizing these travelers in groups for analysis of previous DENV exposure.