RNA interference (RNAi) provides an experimental tool for functional genomics analysis. We screened a genome-wide RNAi library to identify new genes involved in lung cancer cell proliferation. 72 % from the 257 genes identified were involved in general gene expression processes, 16 % were of unknown function or unrelated to proliferation, and 12% consisted of uncharacterized genes. These last sets of genes provide potential novel targets for lung cancer treatment.