Abstract Aims The aim of this study was to analyse the role of inflammation and established clinical scores in predicting acute kidney injury (AKI) after acute coronary syndromes (ACS). Methods and results In a prospective multicentre cohort including 2034 patients with ACS undergoing percutaneous coronary intervention, high-sensitivity C-reactive protein (hsCRP), neutrophil count, neutrophil-to-lymphocyte ratio (NL-ratio), and creatinine were measured at the index procedure. AKI (n = 39, defined according to RIFLE criteria) and major cardiovascular and cerebrovascular events were adjudicated after 1 year. Associations between inflammation, AKI, and cardiac death (CD) were assessed by C-statistics and Cox proportional hazard models with log-rank test to compare survival. Patients with ACS with elevated neutrophil count >7.8 × 109/L, NL-ratio >5, combined neutrophil-count/creatinine, or NL-ratio/creatinine at baseline showed a higher incidence of AKI (all P < 0.05) and CD (all P < 0.001). The risk of AKI, CD, and their combination was increased in patients with higher neutrophil count/creatinine (heart rate (HR) = 3.7, 95% cardiac index (CI) 1.9–7.1; HR = 2.7, 95% CI 1.6–4.6; HR = 3.2, 95% CI 2.1–4.9); NL-ratio/creatinine (HR = 2.1, 95% CI 1.6–4.1; HR = 2.2, 95% CI 1.3–3.8; HR = 2.3, 95% CI 1.5–3.5); and hsCRP (HR = 1.8, 95% CI 0.9–3.5; HR = 2.2, 95% CI 1.3–3.6; HR = 1.9, 95% CI 1.2–2.8) after adjustment for age, diabetes, hypertension, previous heart failure, kidney function, haemodynamic instability at admission, statin, and renin–angiotensin–aldosterone antagonists use. Subjects with higher GRACE score 1.0/NL-ratio had higher rate of AKI, CD, and both (HR = 1.4, 95% CI 0.5–4.2; HR = 2.7, 95% CI 1.3–5.9; HR = 2.1, 95% CI 1–4.3). Conclusions Inflammation markers may predict AKI after correction for renal function at the index procedure. hsCRP performed better than the NL-ratio. However, the integration of inflammation markers to traditional risk factors or scores does not add prognostic information. Trial registration ClinicalTrials.gov, NCT01000701.