RNA interference (RNAi) is a process in which double-stranded RNA triggers the silencing of gene expression in a sequence-specific manner. In mammalian cells, approximately 21-nucleotide small interfering RNA duplexes guide cognate mRNA degradation in a sequence-specific manner by RNA-induced silencing complex. RNAi was successfully applied to inhibit different stages of HIV-1 replication. Recent viral and host cell targets for RNAi that have been used to inhibit HIV-1 are described. The problem with the delivery of RNA duplexes to the target cells and the strategies used by HIV-1 to escape inhibition by RNAi are also discussed.