BACKGROUND: Left ventricular ejection fraction (LVEF) is the most widely used parameter to evaluate the cardiac function in patients with heart failure (HF). However, the association between LVEF and contrast-induced nephropathy (CIN) is still controversial. Therefore, the aim of this study is to evaluate the association of LVEF with CIN and long-term mortality following coronary angiography (CAG) or intervention in patients with HF. METHODS: We analyzed 1,647 patients with HF (New York Heart Association [NYHA] or Killip class >1) undergoing CAG or intervention, including 207 (12.57%) patients with reduced LVEF (HFrEF), 238 (14.45%) with mid-range LVEF (HFmrEF) and 1,202 (72.98%) with preserved LVEF (HFpEF). CIN was defined as an absolute increase of ≥0.5 mg/dL or a relative increase of ≥25% from baseline serum creatinine within 48-72 h after contrast medium exposure. Multivariable logistic regression and Cox proportional hazards regression analyses were performed to identify the association between LVEF, CIN and long-term mortality, respectively. RESULTS: Overall, 225 patients (13.7%) developed CIN. Individuals with lower LVEF were more likely to develop CIN (HFrEF, HFmrEF and HFpEF: 18.4%, 21.8% and 11.2%, respectively; P<0.001), but without a significant trend after adjusting for the confounding factors (HFrEF vs HFpEF: odds ratio [OR] =1.01; HFmrEF vs HFpEF: OR =1.31; all P>0.05). However, advanced HF (NYHA class >2 or Killip class >1) was an independent predictor of CIN (adjusted OR =1.54, 95% confidence interval [CI], 1.07-2.22; P=0.019). During the mean follow-up of 2.3 years, reduced LVEF (HFrEF group) was significantly associated with increased mortality (HFrEF vs HFpEF: adjusted hazard ratio =2.88, 95% CI, 1.77-4.69; P<0.001). CONCLUSION: In patients with HF undergoing CAG or intervention, not worsened LVEF but advanced HF was associated with an increased risk of CIN. In addition, reduced LVEF was an independent predictor of long-term mortality following cardiac catheterization.