The present study investigated whether peroxynitrite (ONOO-)-elicited cytotoxicity on human brain vessel smooth muscle cells (HBVSMCs) was related to alteration in programmed cell death 4 (PDCD4) gene expression. Cell viability, morphological changes and apoptosis were determined by methylthiazoletetrazolium (MTT) assay, acridine orange staining and flow cytometry, respectively. Expressions of PDCD4 at both mRNA and protein levels were examined by RT-PCR and Western blot respectively. Protein expressions of caspase-3, Bcl-2 and Bax were detected by Western an increased apoptotic rate of HBVSMCs after treatment with ONOO-. ONOO- was able to upregulate mRNA and protein expressions of the PDCD4 gene. Moreover, protein expressions of caspase-3 and Bax were significantly increased, whereas the expression of Bcl-2 was markedly decreased in response to exposure of ONOO-. This study demonstrates, for the first time, that the PDCD4 gene is involved in ONOO-- induced apoptosis in HBVSMCs.