© The Author(s) 2022.Contrast-induced nephropathy (CIN) is associated with increased mortality and morbidity. The present study investigated the role of systemic immune inflammation index (SII) in predicting the risk of developing CIN after carotid artery angiography (CAAG). This study included 262 patients who underwent CAAG for symptomatic carotid artery stenosis (CAS). Simultaneous carotid stenting was applied to 232 of these patients. CIN was defined as an increase in serum creatinine level ≥.5 mg/dL or ≥25% above baseline within 72 hours after the procedure. The SII score was calculated as platelet × neutrophil/lymphocyte counts. Patients who developed CIN, had higher glucose (P =.009), total cholesterol (P <.001), low density lipoprotein cholesterol (<.001), and high sensitivity C-reactive protein (P =.001) levels, as well as greater neutrophil counts (P <.001), platelet counts (P <.001), neutrophil–lymphocyte ratio (P <.001), and SII score (P <.001) than those who did not develop CIN. The Receiver Operating Characteristic analysis showed that at a cutoff of 519.9, the SII exhibited 80% sensitivity and 64% specificity for detecting CIN. SII levels on admission were independently associated with CIN development after CAAG in patients with CAS.