Phenotypic modification of dorsal root ganglion (DRG) neurons represents an important mechanism underlying neuropathic pain. However, the nerve injury-induced molecular changes are not fully identified. To determine the molecular alterations in a broader way, we have carried out cDNA array on the genes mainly made from the cDNA libraries of lumbar DRGs of normal rats and of rats 14 days after peripheral axotomy. Of the 7,523 examined genes and expressed sequence tags (ESTs), the expression of 122 genes and 51 expressed sequence tags is strongly changed. These genes encompass a large number of members of distinct families, including neuropeptides, receptors, ion channels, signal transduction molecules, synaptic vesicle proteins, and others. Of particular interest is the up-regulation of γ-aminobutyric acid_A receptor α5 subunit, peripheral benzodiazepine receptor, nicotinic acetylcholine receptor α7 subunit, P2Y1 purinoceptor, Na⁺ channel β2 subunit, and L-type Ca²⁺ channel α2δ-1 subunit. Our findings therefore reveal dynamic and complex changes in molecular diversity among DRG neurons after axotomy.