Aim: To determine whether up-regulation of basic fibroblast growth factor (bFGF) in VX2 cells reduces tumor necrosis. Materials and Methods: VX2 cells were transfected with expression vector containing cDNA of rabbit bFGF. Stable clones producing rabbit bFGF (bFGF-VX2) were selected. bFGF-VX2 (n=5) or non-transfected VX2 (control) (n=5) cells were implanted into leg muscle of 10 rabbits. The tumors were characterized 21 days after grafting. Results: Overexpression of bFGF by VX2 tumors significantly reduced necrosis (p<0.0223) and increased cell viability (p<0.0223), without effect on the mean vascular density. bFGF concentration was significantly higher in bFGF-VX2 tumors (p<0.0062) and negatively correlated with tumor volume at day 21 (rho=-0.927, p<0.0034). Vascular endothelial growth factor concentration was significantly lower in bFGF-VX2 tumors (p<0.0105) and negatively correlated with the bFGF concentration of tumors (rho=-0.903, p<0.0067). Conclusion: The overexpression of bFGF in VX2 cells increased tumor viability and reduced necrosis, making the evaluation of long-term anticancer therapies possible in this model.