After propensity score matching, the incidence of AKI in the CRP/albumin ratio ≥ 0.1 group was significantly higher than that in the CRP/albumin ratio < 0.1 group, and a preoperative CRP/albumin ratio ≥ 0.1 was significantly associated with an increased incidence of AKI after radical cystectomy among elderly patients. Here, CRP is linked to acute kidney injury.