Background. Elevated preprocedural N-term pro-B-type natriuretic peptide (NT-pro-BNP) and postprocedural cardiac troponin I (cTnI) are related to a poor cardiac outcome in the non-diabetic population. We hypothesized that preprocedural NT-pro-BNP might be a useful marker in predicting periprocedural myocardial injury (PMI) following elective percutaneous coronary intervention (PCI) in type 2 diabetes (T2D). Methods. We prospectively enrolled 1194 consecutive diabetic patients with normal cardiac function and preprocedural cTnI who were successfully undergoing elective PCI. Preprocedural NT-pro-BNP levels were assessed at admission, and PMI was evaluated by analysis of cTnI within 24 hours. The relationship between preprocedural NT-pro-BNP levels and the peak values of cTnI after PCI was examined. Results. Patients with high baseline NT-pro-BNP levels had higher postprocedural cTnI levels (beta = 0.123, p < 0.001). In the multivariable model, NT-pro-BNP was associated with higher risk of postprocedural cTnI elevation above 1 x upper limit of normal (ULN, OR, 3.13; 95% CI, 1.51-6.50; p = 0.002), 3 x ULN (OR, 2.44; 95% CI, 1.17-5.08; p = 0.018), 5 x ULN (OR, 3.18; 95% CI, 1.44-7.0; p = 0.004), respectively. Moreover, the incidence of cTnI elevation was higher in patients with the upper tertile of NT-pro-BNP levels than that in ones with the lower tertile of NT-pro-BNP levels (> 1 x ULN: 63.1% vs. 50.0%, p < 0.001; > 3 x ULN: 39.2% vs. 31.9%, p = 0.032; > 5 x ULN: 30.4% vs. 21.9%, p < 0.006; respectively). Conclusions. Our data, for the first time, demonstrated that increased preprocedural NT-pro-BNP levels were strongly and independently associated with a higher risk of PMI, suggesting that baseline NT-pro-BNP level might be a useful marker for predicting PMI following PCI in diabetic patients without cardiac dysfunction.