The formation of atherosclerotic changes leads to dysfunction in numerous cell types, especially endothelial cells. In the current experiment, we aimed to show the therapeutic effect of Docosahexaenoic acid on palmitic-induced atherosclerotic changes in the human endothelial lineage. Human Umbilical Vein Endothelial cells were incubated with 1 mM palmitic acid for 48 hours and then exposed to 40 mu M docosahexaenoic acid for next 24 hours. Cellular atherosclerosis and lipid removal were confirmed by the application of Oil red O solution. The cell survival rate was studied by using MTT assay and flow cytometry analysis of Annexin V. We also measured the protein level of tumor necrosis factor-alpha and granulocyte-macrophage colony-stimulating factor by immunofluorescence imaging. The transcription level of genes participating in the atherosclerosis signaling pathway was monitored in atherosclerotic endothelial cells before and after treatment with docosahexaenoic acid. The viability of the cells was reduced after 48 hours incubation with palmitic acid. It is noteworthy that the number of viable endothelial cells was increased after exposure to docosahexaenoic acid. Compared with the cells that received palmitic acid, Oil red O staining showed a decrease in the cellular content of fatty acid after incubation with docosahexaenoic acid (P < 0.05). PCR array indicated that the modulation of key genes played a role in atherosclerosis and reached near-control levels. These data support the notion that incubation of atherosclerotic human endothelial cells with docosahexaenoic acid could return the detrimental effects of palmitic acid by modulation of the atherosclerosis signaling pathway.