Background: Bevacizumab (BV)-containing chemotherapy has been established as the standard first-line treatment for metastatic colorectal cancer (mCRC). However, no biomarkers have been established to predict the clinical benefit of BV for patients (pts) with mCRC. Methods: Blood samples were collected in EDTA before the first-line treatment with BV+mFOLFOX6 or +XELOX for mCRC. Plasma samples were analyzed at Roche Diagnostics Ltd. (Penzberg, Germany) using IMPACT-2 (Roche proprietary multiplex enzyme-linked immunosorbent assay platform). Median values of pICAM-1 and pIL-8 were used as cut-off points to categorize pts into the low and high groups. Progression free survival (PFS) and overall survival (OS) were compared between two groups, using Cox proportional hazards model. Results: Among 102 pts enrolled between January 2014 and April 2015, 100 (53 BV+mFOLFOX6 and 47 BV+XELOX) were eligible. Median PFS was 11.4 months [95% CI, 9.5-13.0]. Response rate was 64.6 % [53.3-74.9]. pICAM-1 and pIL-8 were measured in 99 pts and the median values were 190.0 ng/ml [range, 58.0- 1080.1] and 311.5 pg/ml [range, 83.2-4541.4], respectively. The hazard ratios of PFS and OS between the high and low pICAM-1 groups were 2.08 [95%CI, 1.28-3.40, p = 0.003] and 2.04 [0.92-4.50, p = 0.079], respectively. The hazard ratios of PFS and OS between the high and low pIL-8 groups were 1.63 [95%CI, 1.00-2.65, p = 0.048] and 3.42[1.57-7.44, p = 0.002], respectively. Conclusions: High pICAM-1 and pIL-8 were associated with short PFS and OS of mCRC pts treated with BV-containing chemotherapy, suggesting that pICAM-1 and pIL-8 could be predictive markers for prognosis of mCRC treated with BV. Clinical trial information: UMIN000012442.