Tribble3 (TRB3), a mammalian homolog ofDrosophilatribbles, slows cell-cycle progression, and its expression is increased in response to various stresses. The aim of this study was to investigate the role of theTRB3gene in macrophage apoptosis induced by oxidized low-density lipoprotein (ox-LDL). We found that, in human monocyte-derived macrophages, TRB3is upregulated by ox-LDL in a dose- and time-dependent manner.