Background Data are limited regarding the risk of contrast-induced nephropathy (CIN) for patients after the second contrast exposure. Objective To examine the risk of CIN after the second contrast exposure in patients of acute coronary syndrome (ACS) with chronic kidney disease (CKD). Methods Patients of ACS scheduled for a second elective PCI. Patients were required to have an estimated creatinine clearance (CrCl) between 15 and 60 ml/min. The value of serum creatinin (sCr) prior to the second contrast exposure must not be ≥ 25% or ≥ 88.4 μmol/L compared to baseline. CIN was defined as an increase of sCr ≥ 25% from baseline within 48-72 h after the second contrast exposure. The primary end-point was risk of developing CIN. Results Thirty-nine patients completed the study. The average of interval between contrast exposures was 116 ± 64 h, contrast volume was 266 ± 100 mL and length of hospitalization was 8.3 ± 4.7 days. The incidence of CIN in the overall study population was 10.3%. There was not change significantly in average sCr and CrCl after the second contrast exposure (sCr 1.52 ± 0.62 vs. 1.54 ± 0.60 mg/dL baseline, P = 0.75; CrCl (40.68 ± 14.46 vs. 39.16 ± 12.10 mL/min baseline, P = 0.26). None of the patient was death in 30 days. One (2.6%) of the patients who developed CIN required dialysis in-hospital. Conclusion Our findings suggest that patients with prior renal dysfunction are not increased risk of developing CIN after the second contrast exposure. This cohort may be benefit from sufficient prophylaxis. Background Data are limited regarding the risk of contrast-induced nephropathy (CIN) for patients after the second contrast exposure. Objective To examine the risk of CIN after the second contrast exposure in patients of acute coronary syndrome (ACS) with chronic kidney disease (CKD ) Methods Patients of ACS scheduled for a second elective PCI. Patients were required to have an estimated creatinine clearance (CrCl) between 15 and 60 ml / min. The value of serum creatinin (sCr) prior to the second contrast exposure must not be ≥ 25% or ≥ 88.4 μmol / L compared to baseline. CIN was defined as an increase of sCr ≥ 25% from baseline within 48-72 h after the second contrast exposure. The primary end-point was risk of developing CIN. Results Thirty -nine patients completed the study. The average of interval between contrast exposures was 116 ± 64 h, contrast volume was 266 ± 100 mL and length of hospitalization was 8.3 ± 4.7 days. The incidence of CIN in the overall study population was 10.3%. There was no change significantly in average sCr and CrCl after the second contrast exposure (sCr 1.52 ± 0.62 vs. 1.54 ± 0.60 mg / dL baseline, P = 0.75; CrCl (40.68 ± 14.46 vs. 39.16 ± 12.10 mL / min One (2.6%) of the patients who developed CIN required dialysis in-hospital. Conclusion Our findings suggest that patients with prior renal dysfunction are not increased risk of developing CIN after the second contrast exposure. This cohort may be benefit from sufficient prophylaxis.