A meeting on chromosome 9 was held on Tuesday, 27 October 1998 in Denver, with 38 participants (see appendix). Since the last meeting several of the positional cloning efforts on chromosome 9q have come to fruition, and the most detailed discussion was on 9p. Dr Ian Dunham from the Sanger Centre explained the strategy to be used for sequencing chromosome 9, and encouraged collaboration in the preparatory mapping. He indicated that some priority could be given to those regions where people in the field had a strong interest and could identify relevant PAC clones. At this short meeting it was clearly not possible to construct a comprehensive map of chromosome 9, and it was decided that efforts should be made to maintain links to sources of information on the chromosome 9 web page (http:@www.gene.ucl.ac.uk/chr9/). The discussions at the meeting are summarized in four sections: 9p, 9cen-q31, 9q32-9q34 and comparative mapping. Many of the posters presented at the meeting were also presented at the ASHG meeting (28-31 October 1998). They are listed here and are published in The American Journal of Human Genetics, vol. 63 (supplement). Abstracts for posters presented only at this meeting are appended to this report.