Currently, no prospective data exists to support a "stop-and-go" modified FOLFOX6 regimen with bevacizumab in metastatic colorectal cancer (mCRC) patients. This study aimed to evaluate the efficacy and safety of this regimen in first-line mCRC patients. Eligible patients (age ≥20 years) had previously untreated mCRC; Eastern Cooperative Oncology Group performance status of 0-2; and adequate hematologic, hepatic, and renal function. The modified FOLFOX6 regimen and bevacizumab (5 mg/kg) was administered intravenously every 2 weeks. After 8 cycles, patients received maintenance therapy with simplified LV5FU2 and bevacizumab until completion of 8 cycles or disease progression. After maintenance therapy, patients received another 8 cycles of modified FOLFOX6 with bevacizumab until completion of 8 cycles or disease progression. We recruited 50 patients between August 2007 and January 2009. The overall response rate was 48% (80% confidence interval [CI]; 38.2-58) with outcomes as follows: complete response, n = 1; partial response, n = 23; stable disease, n = 21; progression, n = 1; and not evaluated, n = 4. Median time to treatment failure was 7.7 months (80% CI: 6.2-8.0), and median progression-free survival was 12.8 months (80% CI: 10.8-14). Grade 3/4 toxicities included neutropenia (40%), nausea (4%), diarrhea (14%), thrombosis (4%), and hypertension (4%) et al. Grade 1, 2, or 3 peripheral neuropathy was reported in 38%, 40%, and 10% of patients, respectively. The stop-and-go modified FOLFOX6 and bevacizumab regimen is effective and well tolerated as first-line chemotherapy for mCRC patients.