Diagnosis of human immunodeficiency virus-1 (HIV-1) infection requires the collection of either serum or oral fluid that is subsequently tested for the presence of antibodies to HIV-1. The effective use of oral fluid for the detection of HIV antibodies is contingent on stabilization of immunoglobulins in the sample through the use of preservatives. Oral fluid preservatives also contain agents that can disrupt and inactivate viruses. This study demonstrates the virucidal activity of a commercially available oral fluid preservative against HIV-1 using a sensitive 28-day cell culture assay designed to detect infectious virus. The results demonstrate that a 5-log reduction in viral titer is obtained when equal volumes of HIV-1 viral stocks and the preservative are mixed. The data provide strong evidence that preserved oral fluid samples from infected individuals are noninfectious for HIV-1.