A wide variety alterations are common in brains of aged individuals. Proteomatic analysis is a new power tool to reveal such changes at protein level. The two-dimensional electrophoresis (2-DE) was employed to compare the global protein patterns between adult and aged murine brains. One hundred and fifty micrograms of murine brain protein extracted with 5 mol/L urea, 2 mol/L thiourea, 2% CHAPS plus 2% SB3-10 was run immobilized pH gradient (IPG) isoelectric focusing electrophoresis as the first dimension, and then horizontal SDS-PAGE as the second dimension. The relative standard deviations(coefficient of variation) for protein number, pI, molecular mass and volume of protein in three different experiments were 4.43%±0.25%, 8.76%±5.14%, 13.00%±4.22% and 10.84%±9.16%, respectively. Totally, 996 and 1 256 protein spots were obtained in adult and aged murine brain map, repectively, of which 8 spots increased and 20 spots decreased in quantity. Furthermore, 4 spots were missing and 14 new spots emerged in aged murine brain compared with adult mice. The differentially displayed proteins between adult and aged murine brain are useful for diagnosing brain degenerative disorders.