BPVs are double stranded DNA viruses that can infect several species other than the natural host, cattle, including equids. In equids, BPV-1, and, less commonly BPV-2, infection gives rise to fibroblastic tumours of the skin. Whilst a causal relationship between BPV-1/2 and equine sarcoids is now well established, how the disease is transmitted is not known. In this study we show BPV-1 DNA can be detected in flies trapped in the proximity of sarcoid-affected animals. Sequence analysis of the BPV-1 LCR from flies indicates that flies harbour BPV-1 LCR sequence variants II and IV which are commonly detected in equine sarcoids. These data suggest that flies may be able to transmit BPV-1 between equids.