ATCC reference strain of respiratory syncytial virus A-2 (VR-1302), which was originally isolated from the lower respiratory tract of an infant (Lewis et al., 'Med. J. Aust. 2 (1961) 932'), is contaminated with adenovirus type 1. The presence of adenovirus was deduced from microscopic observation of CPE in HEp-2 cells and confirmed by electron microscopy, PCR, serological typing and immunofluoresence. Since RSV A2 is used worldwide as a representative virus of RSV type A viruses, and because the ATCC is often cited as the source of the parent stock, we considered it important to bring these findings to the attention of the wider community.