Background: Frailty has been shown to be a good predictor of post-operative complications and death in patients undergoing gastrointestinal surgery. The aim of this study was to analyse the differences between frail and non-frail patients undergoing colorectal cancer surgery, as well as the impact of frailty on long-term survival in these patients.Methods: A cohort of 149 patients aged 70 years and older who underwent elective surgery for colorectal cancer was followed-up for at least 5 years. The sample was divided into two groups: frail and non-frail patients. The Canadian Study of Health and Aging-Clinical Frailty Scale (CSHA-CSF) was used to detect frailty. The two groups were compared with regard to demographic data, comorbidities, functional and cognitive statuses, surgical risk, surgical variables, tumour extent, and post-operative outcomes, which were mortality at 30 days, 90 days and 1 year after the procedure. Univariate and multivariate analyses were also performed to determine which of the predictive variables were related to 5-year survival.Results: Out of the 149 patients, 96 (64.4%) were men and 53 (35.6) were women, with a median age of 75 years (IQR: 72-80). According to the CSHA-CSF scale, 59 patients (39.6%) were frail, and 90 patients (60.4%) were not frail. Frail patients were significantly older and had more impaired cognitive status, worse functional status, more comorbidities, more operative mortality, and more serious complications than non-frail patients. Comorbidities, as measured by the Charlson Comorbidity Index (p=0.001); the Lawton-Brody Index (p=0.011); failure to perform an anastomosis (p=0.024); nodal involvement (p=0.005); distant metastases (p<0.001); high TNM stage (p=0.004); and anastomosis dehiscence (p=0.013) were significant univariate predictors of a poor prognosis in univariate analysis. Multivariate analysis (Cox regression) of long-term survival, with adjustment for age, frailty, comorbidities and TNM stage, showed that comorbidities (p=0.002; HR:1.30; 95% CI:1.10–1.54) and TNM stage (p=0.014; HR:2.06; 95% CI:1.16-3.67) were the only independent risk factors for survival at five years.Conclusions: Frailty is associated with poor short-term post-operative outcomes, but it does not seem to affect long-term survival in patients with colorectal cancer. Instead, comorbidities and tumour stage are good predictors of long-term survival.