Abstract: Objective To assess the efficacy and safety of bevacizumab plus FOLFIRI for the first line treatment in metastatic colorectal cancer (mCRC) patients. Methods From May 2008 to July 2009，40 previously untreated mCRC patients received treatment of FOLFIRI (n=20) or FOLFIRI plus Bevacizumab(n=20).The treatment continued until disease progression or unacceptable toxicity.The data were retrospectively analyzed. Results All patients were evaluable for response,survival and toxicity analysis.The objective response rate of FOLFIRI and FOLFIRI plus Bevacizumab regimen groups was 25％ (5/20) and 60％ (12/20),respectively (χ²=5.013,P=0.025).The median disease-free survival (DFS) of FOLFIRI and FOLFIRI plus bevacizumab group was 5.1 and 10.1 months,respectively (χ²=9.703,P=0.002).The one-year survival rate was 48％ and 70%,and the median overall survival (OS) was 11.0 and 18.0 months,respectively,with significant difference among the two treatment groups (χ²=5.852,P=0.016).The common toxicity profiles of FOLFIRI and FOLFIRI plus bevacizumab regimens were diarrhea and neutropenia,while the toxicity related to bevacizumab was consistent with that documented in previous literature such as hypertension,hemorrhage,cardiac,and proteinuria toxicity. Conclusion The addition of bevacizumab to FOLFIRI regimen significantly improves the response rate.DFS and OS in first-line treatment for patients with mCRC and its toxicity is well tolerated.