Sorafenib (BAY 43-9006) is a potent inhibitor of VEGFR-2 kinase (0.22±0.09 mM), VEGFR-2 (0.84 mM), VEGFR2 kinase (8.99 nM), EGFR kinase (0.76 mgm L−1), RAF1 (6 nM). Sorafenib (BAY 43-9006) exhibits the greatest inhibitory potency toward RAF1 (IC50 = 6 nM).