Background: Retroviruses encode a very limited number of proteins and therefore must exploit a wide variety of host proteins for completion of their lifecycle. Methods: We performed an insertional mutagenesis screen to identify novel cellular regulators of retroviral replication. Results: This approach identified the ATP-dependent chromatin remodeler, chromodomain helicase DNA-binding protein 2 (CHD2), as well as the highly related CHD1 protein, as positive regulators of both MLV and HIV-1 replication in rodent and human cells. RNAi knockdown of either CHD2 or the related CHD1 protein, in human cells resulted in a block to infection by HIV-1, specifically at the level of transcription. Conclusions: These results demonstrate that CHD1 and CHD2 can act as positive regulators of HIV-1 gene expression.