Enveloped virus vectors are used in a wide variety of applications. We have discovered that treatment of cultured cells with phosphatidylserine (PS) liposomes can increase virus vector infection by up to 20-fold. This effect does not abrogate virus receptor requirements, is specific to PS compared to other phospholipids, and is limited to enveloped viruses. Furthermore, the enhancement of infection does not occur through increases in virus receptor levels or virus binding, indicating that virus fusion is enhanced. The liposomes are easily generated, store well, and allow enhanced infection with a variety of virus vectors and cell types.