Background: Ischemia time during partial nephrectomy (PN) is among the greatest determinants of acute kidney injury (AKI). Whether this association is affected by the preoperative risk of AKI has never been investigated. Objective: To assess the effect of the interaction between the preoperative risk of AKI and ischemia time on the probability of AKI during PN. Design, setting, and participants: Data of 944 patients treated with on-clamp PN for cT1 renal tumors were extracted from the Registry of Conservative and Radical Surgery for Cortical Renal Tumor Disease (RECORD2) database, a prospective multicenter project. Outcome measurements and statistical analysis: We estimated the preoperative risk of AKI (defined according to the risk/injury/failure/loss/end-stage [RIFLE]