Human immunodeficiency virus (HIV) type 1 (HIV-1) integrase is an underutilized drug target for the treatment of HIV infection. One limiting factor is the lack of costructural data for use in the rational design or modification of integrase inhibitors. Tn5 transposase is a structurally well characterized, related protein that may serve as a useful surrogate. However, little data exist on inhibitor cross-reactivity. Here we screened 16,000 compounds using Tn5 transposase as the target and identified 20 compounds that appear to specifically inhibit complex assembly. Six were found to also inhibit HIV-1 integrase. These compounds likely interact with a highly conserved region presumably within the catalytic core. Most promising, several cinnamoyl derivatives were found to inhibit HIV transduction in cells. The identification of integrase inhibitors from a screen using Tn5 transposase as the target illustrates the utility of Tn5 as a surrogate for HIV-1 integration even though the relationship between the two systems is limited to the active site architecture and catalytic mechanism.