The generation of arterioles (arteriolargenesis) from capillaries in response to shear stress requires members of the vascular endothelial growth factor (VEGF) and Angiopoietin (Ang) families of growth factors. While Ang1 is known to be involved in pericyte recruitment and VEGF in endothelial growth, how these two signaling pathways interact during cell recruitment to the vessel wall during flow is not clear. To test the hypothesis that both Ang1 and VEGF are required for functional remodelling (generation of arterioles from capillaries as well as new pericyte covered capillaries), we used adenovirus-mediated over-expression of eNOS, Ang1, and the VEGF inhibitor sFlt1, in the fluothane anaesthetised (3-5% in 75%O2) adult rat mesentery after laparotomy as a model of blood flow dependent vascular remodeling. Blood flow and angiogenesis /arteriolargenesis were assessed by intravital and confocal microscopy respectively. The effects of VEGF inhibition and Ang1 inhibition were investigated using Ad-Flt1 and Ad-sTie2 respectively. Ang1+eNOS increased angiogenesis (vascular area 43±3% of mesenetery, p<0.01) compared with eNOS alone (30±1%), and this was inhibited by sFlt1 (33±2%). However, the Ang1 induced increase in pericyte coverage (50±1% vessel coverage compared with 27±2% without Ang1) was enhanced, not inhibited by sFlt1 (65±2%). This was accompanied by an inhibition of the Ang1 induced smooth msucle cell coverage (from 8.6±1.3% to 0%, p<0.01). Thus, in this setting, inhibition of endogenous VEGF signaling impaired VSMC recruitment, but enhanced pericyte coverage. Thus, while VEGF signaling inhibits pericyte recruitment, it is required for VSMC recruitment. These results indicate that the de novo formation of a functional, mature vasculature, with VSMC-containing arterioles requires tight control of endogenous VEGF and exogenous Angiopoietin signaling. Therapeutic vascular remodeling paradigms may therefore require treatments that activate endogenous VEGF, in combination with exogenous Ang1, to effectively remodel the vasculature.