AIM: To investigate the effects of 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) on cell proliferation and apoptosis in ECV304 endothelial cells and related molecular mechanism. METHODS: MTT, Hoechst33258, TUNEL, Flow cytometry, DNA ladder, RT-PCR, Western blot, and electrophoretic mobility shift assay (EMSA) analysis were employed. RESULTS: The 15d-PGJ2 induced apoptosis in ECV304 endothelial cells in a dose-dependent manner (the percentage of apoptosis was enhanced from 10.0%±1.3% to 32.8%±1.6%), which was accompanied by inhibition of NF-κB and AP-1 DNA binding activity, down-regulation of c-myc, upregulation of Gadd45 and p53, and activation of p38 kinase. However, the expression of p21 was found no significant change. CONCLUSION: peroxisome proliferator-activated receptor gamma ligand, 15d-PGJ2, can inhibit proliferation and induce apoptosis in ECV304 endothelial cells through different mechanisms.