We describe a novel mechanism of viral RNA eradication by an oligodeoxynucleotide A (ODN A) directly in HIV virions. The ODN A consists of an antisense and a passenger strand, and was designed to target the polyp-urine tract (PPT) of HIV-1, a conserved region of the viral genome. It leads to HIV reverse transcriptase/ribonuclease H (RT/RNase H)-dependent degradation of the RNA in viral particles. Illimaquinone, a specific inhibitor of RNase H, activity of HIV RT/RNase H, prevents RNA cleavage. The effect of the ODN A is sequence-specific and the passenger strand is important, since a lack or alteration of this strand reduces the antiviral activity of the ODN. ODN A has a stronger antiviral effect compared to a control ODN CO, targeted to a site outside of the PPT. The pretreatment with ODN A strongly reduced the infectivity of virions in cell culture in the absence of any DNA carriers or detergents.