A web-based synteny visualization tool that enhances the original functionalities of GSV by allowing biologists to upload their own datasets and visualize the synteny among multiple genomes simultaneously in a single integrated view. Users can navigate through all the selected genomes in either pairwise or multiple viewing mode to examine conserved genomic regions as well as the accompanying genome annotations. Besides serving users who manually interact with the web server, mGSV also provides Web Services for machine-to-machine communication to accept data sent by other remote resources. The novel design and the implementation of mGSV provide the research community with an important alternative to currently available tools. Multiple genomes can be presented in a single integrated view with an enhanced user interface.