Background: For the last few years, sunitinib has been considered the standard treatment for first-line metastatic renal cell carcinoma, but in 2010 a new drug pazopanib had been approved for treatment in this setting. Recent data from the COMPARZ and PISCES study seem to suggest a non-inferiority of pazopanib confronted with sunitinib in PFS and OS and a patients’ preference for pazopanib if we consider quality of life parameters. The aim of our study is to investigate whether polymorphisms of VEGF and VEGFR can influence PFS and OS when patients are treated either with sunitinib or pazopanib as first-line treatment. Methods: 97 histologic samples of mRCC patients were tested for VEGF-A, VEGF-C, and VEGFR-1, 2, 3 single nucleotide polymorphisms (SNPs). Patients’ progression free survival (PFS) and overall survival (OS) were analyzed for first-line treatment. Results: In patients treated with sunitinib VEGF-A rs833061 resulted significant in PFS (CC+CT vs TT, p < 0.0001) and OS (p < 0.0001). VEGF-A rs699947 was significant for PFS (AA+AC vs. CC) p = 0.0001) and OS (p < 0.0001). VEGF-A rs2010963 was significant in PFS (CC vs. CG vs. GG, p = 0.0001) and in OS (p = 0.0045). VEGR3 rs6877011 was significant in PFS (CC vs. CG, p = 0.0075) and OS (p = 0.0001). At multivariate analysis rs833061, rs2010963, and rs68877011 were significant in PFS. rs833061 and rs68877011 were independent factors in OS. In the pazopanib treated groups of patients VEGF-A rs833061 resulted significant in PFS (TT+CT vs. CC p = 0.027) Conclusions: In our analysis patients with CC or CT polymorphism of rc833061 had a favourable PFS and OS if treated with sunitinib instead patients treated with pazopanib seems to have benefit if CT+TT polymorphism, A polymorphism rs699947 and G polymorphism of rs2010963 seem to have a better PFS and OS in first line with sunitinib. Patients with C polymorphism of rs6877011 and G polymorphism of rs307822 seem equally to have a favourable impact in first-line therapy with sunitinib. Our data seem to suggest that biology could have a role in the choice of first-line treatment for mRCC patients. Further data will be presented at the Symposium.