Background: Anti-angiogenic drugs represent a cornerstone of metastatic colorectal cancer (mCRC) patients (pts) treatment. Currently, no prognostic/predictive biomarkers were validated to identify who is more likely to benefit from these agents. We performed at our Centre a retrospective research to assess potential prognostic/predictive factors in this population. Methods: We retrospectively collected laboratory, radiological and clinical data of mCRC pts receiving anti-angiogenic agents at the Medical Oncology Unit of Cagliari University Hospital (2018- 09/2023) in order to assess their correlation with overall survival (OS) and progression free survival (PFS) from the treatment start. Statistical analysis was performed with MedCalc (survival distribution: Kaplan-Meier; survival comparison: log-rank test; cut-off: ROC curves). Results: Globally, 32 mCRC pts were included in our research (19 male, 13 female; 12 RAS wild-type, 21 left-sided primary). 10 received anti-angiogenic drugs in the 1st-line, 12 in the 2nd-line (bevacizumab and aflibercept) and 10 in 1st-2nd line. Median OS was 34.8 months (m) (95%CI:24.7-41.6). We observed a statistically significant improve in OS (34.8 months [m] versus [vs] 8.2 m) in pts with higher monocyte count (>0.3x10³/μL; 95%CI 26.5-39.5 vs 95%CI 8.2-24.7, p=0.0103, HR 0.01), lower alcalin phosphatase (ALP; <136 U/l; p=0.0001, HR=0.0001; 95%CI 12-39.5 vs 95% CI 8.2-10.4), lactate dehydrogenasis (LDH; <365 U/l; p<0,0001, HR=0.0000006; 95%CI 24.7-39.5 vs 95% CI 8.2-10.4) and platelet to lymphocyte ratio (PLR; ≤253; p<0.0001, HR= 0.00000062; 95%CI 24.7-39.5 vs 95% CI 8.2-10.4). Median PFS was 14.9 m (95% CI 9.5-18.5). The same factors were significantly related to PFS, which was 18.3 m vs 2.7 m for higher monocyte count (95%CI 11.4-22.1 vs 95%CI 2.7-14, p=0.0386, HR=0.05), lower LDH (95%CI 11.4-22.1 vs 95%CI 2.7-8.9, p=0.0024, HR=0.004), lower PLR (95%CI 11.4-22.1 vs 95%CI 2.7-8.9, p=0.0024, HR=0.004) and 18.3 m vs 8.9 m for lower ALP (95%CI 11.4-23.3, p=0.0369, HR=0.04). Furthermore pts not developing bleeding during treatment showed a significant benefit in OS (39.5 m [95%CI 26.5-41.6] vs 8.2 m [95%CI 8.2-12], p< 0.0001, HR 0.000001761) and improved PFS (17.9 m [95%CI 9.9-18.4] vs 2.4 m [95%CI 2.4-2.7]; p<0.0001). Conclusions: Our findings showed a promising prognostic role of baseline monocytes, ALP, LDH and PLR and absence of bleeding occurrence in mCRC patients receiving anti-angiogenic drugs, even if in a limited population. Further larger prospective studies are encouraged for confirmation.