Purpose: To evaluate the cost-effectiveness of the addition of bevacizumab to the irinotecan-fluorouracil (Douillard regimen-CPT-FUFA-) in first-line treatment of metastatic colorectal cancer in a single-institution population. Methods: Controlled, nonrandomized retrospective observational study. Treatment-naive metastatic colorectal cancer patients received CPT-FUFA (January 2000-December 2003; control group) and bevacizumab_CPT-FUFA (January 2007-December 2010; study group). Variables related to: patient, clinical response (number of disease progression or death events, progression-free survival) and treatment (antineoplastic dose reduction, incremental cost/treated patient associated with the addition of bevacizumab). Statistical analysis: median progression-free survival (Kaplan-Meier method), and hazard ratio (Cox regression). Survival curves were compared (Mantel-Haenszel test). Results: In all, 69 patients were included: 32 (57.2 years 95%Cl: 54.0-60.5, 65.6% men) in CPT-FUFA group and 37 (68.1 years 95%Cl: 65.5-70.7, 78.4% men) in bevacizumab_CPT-FUFA group. The disease progression or death events were 29 (90.6%) in CPT-FUFA group and 34 (91.9%) in bevacizunnab_CPT-FUFA group. Median progression-free survival was 10.1 months (95%Cl: 7.1-12.2) in CPT-FUFA and 11.0 months (95%Cl: 7.6-12.6) in bevacizumab_CPT-FUFA (hazard ratio = 1.22; 95%Cl: 0.7-2.1). Dose reductions: irinotecan and fluorouracil 11% (range: 4-20) in 5/32 (15.6%) CPT-FUFA patients and 25% (range: 8-35) in 18/37 (48.6%) bevacizumab_CPT-FUFA patients; Bevacizumab 30% (range: 4-50) in 20/37 (54.1%) bevacizumab_CPT-FUFA patients. The incremental cost associated with the addition of bevacizumab was 12,696.5 (IC95%:10,860.8-14,532.1) euros/patient. Conclusion: The addition of bevacizumab to the irinotecan-fluorouracil regimen, does not improve progression-free survival in our study population but increases costs per treated patient. These results potentially compromise the cost-effectiveness of the Bevacizumab_CPT-FUFA regimen.