Background: In the phase III SOLSTICE study, FTD/TPI plus BEV showed similar efficacy to capecitabine plus BEV as first-line treatment for patients with mCRC ineligible for full-dose combination chemotherapy with oxaliplatin [OX] or irinotecan [IRI] (intensive therapy). We evaluated clinical outcomes of FTD/TPI plus BEV as second- or later lines treatment for vulnerable patients, who were defined to be intolerant to intensive therapy. Methods: This was a multicenter retrospective study of vulnerable patients with unresectable mCRC who received FTD/TPI plus BEV as second- or later lines treatment between May 2014 and October 2020. Main eligibility criteria were histologically proven adenocarcinoma, ECOG PS 0-2, prior chemotherapy for unresectable disease, considered intolerant to intensive therapy, and underwent FTD/TPI plus BEV without prior exposure to at least one key cytotoxic agent (fluoropyrimidines [FP], OX, or IRI). Results: Of 96 patients enrolled from 26 Japanese hospitals, 93 patients were evaluable. Patient characteristics were as follows: median age, 79 years (range 21-90); male, 53%; ECOG PS 0-1, 89%; right-sided primary tumor, 30%; primary tumor resection, 86%; RAS mutant, 63%; BRAF mutant, 1%; second-line treatment, 80%; prior exposure to FP 100%, OX 50%, and IRI 15%. Main reasons for intolerance to intensive therapy were older age (65%), poor PS (20%), and renal failure (5%). Initial dose of FTD/TPI was reduced in 30 (32%) patients. The response rate was 5% and disease control rate was 68%. With median follow-up of 21.6 months, the median progression-free survival, time to treatment failure, and overall survival were 6.3, 4.5, and 18.6 months, respectively. Major grade >3 adverse events were neutropenia (54%), anemia (20%), thrombocytopenia (9%), hypertension (7%), and febrile neutropenia (2%). No treatment-related deaths were observed. The treatment was discontinued in 89 patients due to disease progression (n = 72), patient’s refusal (n = 10), and adverse events (n = 6). After FTD/TPI plus BEV, chemotherapies such as regimens including IRI or OX (n = 20), regorafenib (n = 16), and anti-EGFR antibody monotherapy (n = 7) were performed in 42 patients. Conclusions: FTD/TPI plus BEV as second- or later lines treatment for vulnerable patients with mCRC showed promising clinical activity and acceptable safety profile. This study suggested that FTD/TPI plus BEV could be a treatment option for vulnerable patients with pretreated mCRC. Clinical trial information: UMIN000044136.