The purpose of this study was to assess patient frailty as a risk factor for radical cystectomy (RC) complications. We performed an analysis of prospectively collected data of consecutive patients 80 years of age or older who underwent RC and ureterocutaneostomy in 6 primary care European urology centers. Frailty was measured using a simplified frailty index (sFI) with a 5-item score including: (1) diabetes mellitus; (2) functional status; (3) chronic obstructive pulmonary disease; (4) congestive cardiac failure; and (5) hypertension, with a maximum 5-item score meaning high level of frailty. Within 90 days surgical complications were scored according to the Clavien Classification System (CCS). sFI ≥3 was considered as poor frailty status. Clinical and pathological variables were analyzed as predictors of severe complications (CCS ≥3). One hundred seventeen patients were enrolled. Most patients reported an sFI score of 2 and 3, respectively, 31/117 (26.5%) and 45/117 patients (38.5%). CCS ≥3 occurred in 17/117 patients (14.5%). Patients with sFI ≥3 were significantly older than patients with sFI <3 (median age, 85 years interquartile range (IQR), 82-86 versus 82 years IQR, 80-84; P = .001). Most CCS ≥3 scores occurred in patients with sFI ≥3: 13 (11.1%) versus 4 (3.4%; P = .02). No significative differences were detected in terms of length of hospital stay, pathological stage, and postoperative bowel canalization when related to sFI. sFI ≥3 was an independent risk factor of CCS ≥3 in univariate and multivariate analysis (respectively, odds ratio OR, 3.81 95% confidence interval (CI), 1.16-12.5; P = .02 and OR, 3.1 95% CI, 0.7-13.7; P = .01). Body mass index, age, American Society of Anesthesiologists score ≥3, and pathological stage were not related to CCS ≥3. RC appears feasible in elderly patients with an sFI <3. In cases of sFI ≥3, this choice should be carefully valued, discussed, and possibly avoided because of a higher risk of complications. We used the Frailty index as a risk factor for radical cystectomy (RC) complications. We performed an analysis of data of consecutive patients 80 years of age or older who had undergone RC and ureterocutaneostomy (UCS) in 6 European centers. No differences were detected in terms of length of hospital stay, pathological stage, or postoperative bowel canalization as related to the Frailty index. RC and UCS seem to be a feasible option in frail elderly patients.