Objective To explore the regulation of p38 mitogen-activated protein kinase (MAPK) pathway by West Nile virus (WNV) in human neuroblastoma SH-SY5Y cells and the contributions of p38 MAPK to WNV replication as well as stress and inflammatory response related molecule expression. Methods Total and phosphorylated p38 MAPK levels were analyzed in SH-SY5Y cells incubated with WNV for short (5, 15, 30 and 60 min) and long (12, 24, 48 and 60 h) durations by Western blotting. Dynamic changes of CCAAT/enhancer-binding protein homologous protein (CHOP), interleukin 6 (IL-6), activating transcription factor 6α (ATF6α) and interferon-stimulated gene 15 (ISG15) mRNA expression in WNV infected cells were detected by qRT-PCR. In response to WNV infection, WNV RNA level and CHOP, IL-6, ATF6α and ISG15 mRNA levels were assessed in SH-SY5Y cells transfected with p38 MAPK siRNA. Results Incubation with WNV for short durations enhanced p38 MAPK phosphorylation compared to the untreated control. The p38 MAPK signaling pathway was activated at 12 h and 24 h in WNV-infected SH-SY5Y cells, but down-regulated at 48 h and 60 h. WNV infection led to increased mRNA expression of CHOP, IL-6 and ISG15 and reduced ATF6α mRNA. In comparison with control siRNA transfection, the levels of WNV RNA (P<0.05) and ATF6α mRNA (P<0.01) were increased and CHOP mRNA level was decreased (P<0.05) in WNV-infected SH-SY5Y cells with the p38 MAPK siRNA transfection. Conclusion The p38 MAPK pathway is activated during early stage of WNV infection and such activation may negatively regulate WNV replication. WNV-induced stress response molecules CHOP and ATF6α and proinflammatory cytokine IL-6 production by SH-SY5Y cells are coupled with the regulation of p38 MAPK pathway.