Abstract Summary: A database and website (MPD: Mouse Phenome Database) have been developed to serve as a consolidated home for mouse strain characterization data being generated by the scientific community. Physiological, anatomical and behavioral data are being collected and integrated into a common framework for tabulation by strain and sex. Genotypic data are being collected as well. The current focus is on a set of 40 inbred strains. The MPD as of February 2004 contains approximately 500 phenotypic parameters relevant to human health, voluntarily contributed by several dozen investigators and laboratories. Availability: http://www.jax.org/phenome Supplementary information: Guidelines for investigators who may be interested in contributing data are available at http://aretha.jax.org/phenome/dataguide.html