This paper reports on the initial analysis of protein expression in the mouse cerebellum with the proteomics approach. Proteins from cerebellar tissue homogenates were separated by two-dimensional gel electrophoresis, and the proteins were stained with colloidal Coomassie Blue to produce a high-resolution map of the cerebellum proteome. Selected proteins from this map were digested with trypsin, and the resulting tryptic peptides were analyzed by matrix-assisted laser desorption/ionization mass spectrometry and liquid chromatography-electrospray quadrupole ion trap mass spectrometry. The mass spectrometric data were used to identify the proteins through searches of the SWISSPROT protein sequence database. To date, 30 prominent proteins with various functional characteristics were identified. These data will be used for future studies of differential protein expression in mouse models of neurological disorders.