Introduction Recent studies have suggested that the VEGF inhibitors, Ranibizumab and Aflibercept may be associated with an excess of cardiovascular events, potentially driven by increasing atheroma instability, leading to plaque rupture and clinical events. Inflammation plays a key role in the progression of atherosclerotic plaque and particularly conversion to an unstable phenotype. Here, we sought to assess the in vitro effects of these drugs on the expression of key inflammatory mediators on endothelial cells. Methods Human coronary artery endothelial cells were coincubated for 16h with Ranibizumab (0.11nM) or Aflibercept (0.45nM), as determined by each drug's peak serum concentration (Cmax). Expression at protein (ELISA) and gene (RTPCR) level of inflammatory chemokines CCL2, CCL5 and CXC3L1 as well as gene expression for the cell adhesion molecules VCAM1, ICAM1 and the key NFκb protein p65 was assessed. VEGFA protein levels were also determined. Results Both drugs significantly increased chemokine, cell adhesion molecule (CAM) and p65 expression, while decreasing VEGFA protein secretion. At equivalent Cmax concentrations, Aflibercept was significantly more proinflammatory than Ranibizumab. Reduction of secreted VEGFA levels significantly attenuated inflammatory effects of both drugs, whereas blockade of the VEGFA receptor or silencing of VEGFA gene synthesis alone had no effect, suggesting that binding of drug to secreted VEGFA is crucial in promoting inflammation. Finally, blockade of Tolllike receptor 4 significantly reduced inflammatory effects of both drugs. Conclusion We demonstrated here, for the first time, that both drugs have potent proinflammatory effects, mediated via activation of Tolllike receptor 4 on the endothelial cell surface by drug bound to VEGFA. Further studies are required to investigate whether these effects are also seen in vivo.