Background: In the Sunlight Trial, the combination of FTD/TPI + BEV demonstrated significantly extended Overall Survival (OS) and Progression-Free Survival (PFS), along with an improved Disease Control Rate (DCR), compared to FTD/TPI alone in patients with refractory mCRC. The BeTAS trial aimed to evaluate the real-world effectiveness and safety of the FTD/TPI + BEV combination in patients with refractory mCRC. Methods: We conducted a multicenter, retrospective, observational study involving patients with mCRC who were refractory or intolerant to standard therapies (including oxaliplatin, irinotecan, fluoropyrimidines, anti-VEGF, and anti-EGFR if RAS/BRAF wild-type) and were treated with FTD/TPI + BEV at six university hospitals affiliated with the Galician Research Group on Digestive Tumors (GiTUD) in Northwest Spain. Results: A total of 110 patients were enrolled in the BeTAS trial between July 2019 and August 2023. The median age was 66 years (range 33-88 years), with 62.7% being male. Notably, 18.2% of patients had an ECOG performance status of 2, 50.9% had RAS mutations, 27.3% had three or more metastatic locations, and 72.7% had liver metastases. Additionally, 26.4% had a time since the diagnosis of the first metastases of less than 18 months, and 46.4% were categorized as the poor prognostic Tabernero´s Subgroup. Most patients (77.3%) received FTD/TPI + BEV as a third-line treatment, with 88.9% having received previous anti-VEGF therapy. Notably, 13.6% received FTD/TPI at a dose of 30 mg/m2, and 6.4% received prophylactic GCSF. The median number of cycles received was 4 (range 1-21 cycles). Among 97 evaluable patients, the overall response rate (ORR) was 2.1%, and the disease control rate (DCR) was 46.4%. With a median follow-up of 15.5 months, the median PFS was 4.2 months (95% CI, 3.5-4.9 months), and the median OS was 9.9 months (95% CI, 7.3 - 12.5 months). The most common grade 3-4 toxicities included neutropenia (41.8%), asthenia (7.3%), and hepatic toxicity (5.5%). No treatment-related deaths were reported. Conclusions: The BeTAS trial findings affirm the real-world effectiveness and safety of FTD/TPI + BEV in the context of routine clinical practice, even in a population with a poor prognosis and extensive prior treatment history.