Sorafenib (BAY 43-9006) is a novel oral bis-aryl urea compound originally developed as an inhibitor to RAF kinase for its anti-proliferative property. It also inhibits receptor tyrosine kinases of multiple pro-angiogenic factors such as VEGFR-2/3, Flt-3/ and PDGFR-β. The combination of both its anti-proliferative and anti-angiogenic properties makes sorafenib an attractive agent in cancer treatment. Phase I studies demonstrated that sorafenib was well tolerated, and the recommended phase II dose was 400 mg twice daily continuously. Common toxicities included skin toxicity (rash and hand-foot syndrome), gastrointestinal toxicities (nausea and diarrhea) and fatigue. Anti-tumor activities were observed in multiple tumors types including renal cell carcinoma and hepatocellular carcinoma. Randomized phase III studies in these tumor types are ongoing, and results are eagerly waited.