Considering the lifelong implications of a positive human immunodeficiency virus (HIV) test result, physicians should be aware of the limitations of tests for HIV. A 43-year-old man had a reactive enzyme-linked immunosorbent assay and an indeterminate result on Western blot analysis. The results of subsequent enzyme-linked immunosorbent assay and Western blot tests were interpreted as positive, and the patient was informed that he had HIV infection. Persistently undetectable plasma HIV-1 RNA, combined with normal physical examination findings, CD4+ cell count, and CD4/CD8 ratio, prompted further testing, which revealed that the patient was not infected with HIV. False-positive HIV test results are uncommon, but they can occur. In the appropriate clinical setting, follow-up and the use of other laboratory tests, such as determination of plasma viral load, may help identify such cases.