In response to the growing demand of the scientific community to have access to mutant mice for biomedical research, the Comparative Medicine Program (CMP) of the National Center for Research Resources (NCRR)/NIH has established four Mutant Mouse Regional Resource Centers (MMRRCs) and an electronic network that links the four centers (the Informatics Coordinating Center - ICC). The goals of the MMRRCs are to develop mutant mouse distribution facilities capable of husbandry, cryopreservation, rederivation, phenotypic characterization, maintenance of a mouse resource database and a provision of high-level genetic and microbial quality control. The U42 funding mechanism also supports applied research at each of the MMRRCs that is intended to improve the resource and enhance the NIH biomedical research enterprise. The MMRRC network was established in 1999, the governance and logistics of this complex program have been optimized, mice are being submitted to the MMRRCs and mice are now available for distribution. This proposal requests support for the fourth Annual MMRRC Meeting to be held in March of 2004. The meeting will provide a forum for the MMRRC Program Directors, the ICC Program Director, an External Steering Committee, MMRRC Subcommittee Chairpersons, and other key MMRRC personnel to meet with NCRR program staff to discuss issues relating to advancing the MMRRC and NCRR program goals. In addition, the meeting will provide a forum for other NIH program staff to provide input into the MMRRC concept, and to coordinate efforts with the key representatives of the scientific mouse community, representing NCI (mouse models of cancer), chemically mutagenized mice, gene trapping/embryonic stem cell mouse archives, CRE-LoxP mice, etc. This year's meeting will be 11/2 days and will include a scientific program with relevance to the laboratory mouse. Thus, a portion of the meeting will be open to the general scientific community. The proposed meeting will assure the continued success of the MMRRC program, allow input into improving the program and to provide an educational forum for the scientific and professional community, in keeping with the program aims of the MMRRCs and the NCRR.