We have begun a joint program as part of a coordinated international effort to determine a complete human genome sequence. Our strategy is to map large-insert bacterial clones and to sequence each clone by a random shotgun approach followed by directed finishing. As of September 1998, we have identified the map positions of bacterial clones covering ∼860 Mb for sequencing and completed >98 Mb (∼3.3%) of the human genome sequence. Our progress and sequencing data can be accessed via the World Wide Web (http://webace.sanger.ac.uk/HGP/ orhttp://genome.wustl.edu/gsc/).