Through the proteomic analysis using 2-dimensional electrophoresis, the nicotine addiction-associated proteins were extensively screened in the striatum of rat brains. The nicotine addiction was developed by repeated nicotine injection (0.4mg/kg s.c.), twice daily for 7 days, followed by one challenge injection after a 3 day withdrawal period, and then confirmed by observing a 2.3-fold increase in locomoter activity. The 3 up- and 4 down-regulated proteins were selected and identified to be zinc-finger binding protein-89 (ZBP-89), 2'3'-cyclic nucleotide 3'-phosphodiesterase 1, deoxyribonuclease 1-like 3 (DNase1l3), tandem pore domain halothane inhibited K(+) channel (THIK-2), brain-specific hyaluronan-binding protein (BRAL-1), death effector domain-containing DNA binding protein (DEDD), and brain-derived neurotrophic factor (BDNF) by mass spectrophotometric fingerprinting. Among them, the expression patterns of ZEB-89, DNase1l3, THIK-2, DEDD, and BDNF mRNAs were found to be coincident with those of cognate proteins, by using RT-PCR analysis. These proteins could be suggested as drug targets to develop a new therapy for nicotine-associated diseases, as well as the clues to understand the mechanism of nicotine.