Quantitative mapping of genetic interactions (GIs), by simultaneously perturbing gene pairs then measuring the resultant phenotypes, is a powerful tool for understanding complex biological phenomena permitting the unbiased characterization of gene function and the mapping of functional modules and pathways. This discussion will present a GI analysis pipeline to study the functions of HIV host factors through pairwise knockdown of 360 host genes (representing 129,600 combinations) followed by infection with HIV. This work combines a luminescence-based viral infectivity assay to quantify HIV infection with a microscopy-based cellular analysis, allowing us to assemble GI maps of the host factor complexes and pathways mediating the early HIV lifecycle.