Background: Percutaneous coronary intervention (PCI) of calcified lesions has been associated with reduced procedural success and increased complications. There are limited data on the safety and efficacy of PCI in patients with calcified coronary lesions in the drug-eluting stent (DES) era. Methods: A total 1069 consecutive patients underwent PCI with DES were enrolled for the study. Procedural outcomes, in-hospital and 6-month clinical outcomes of angiographically significant calcified lesion group (n=98, 9.1%) were compared with those of angiographically non-significantly calcified group (n=971, 90.9%). Results: Baseline clinical characteristics were similar between two groups. There were more chronic total occlusion (CTO) lesions in the calcified lesion group (10.4% vs. 3.1%, P<0.001). However, acute myocardial infarction (AMI) and diffuse lesions were more common in non-significantly calcified group (28.6% vs. 23.4, P=0.034 and 68.2% vs. 48.9%, P<0.001, respectively). The procedure success rate tended to be higher in non-significantly calcified group (98.7% vs. 94.7%, P=0.053). The intimal dissection was more often in the calcified lesion group (19.7% vs. 11.3%, P=0.001). However, there was no significant difference in survival rate and freedom from major adverse cardiac events (MACEs) between the two groups at 6-month follow up (98.6% vs. 98.1, P=0.503). Conclusion: Coronary calcification was more associated with chronic and significant coronary lesions. Although the angiographically significant calcified coronary lesions were associated with lower procedural success and higher procedural complications but did not exert a negative impact on mid-term clinical outcomes in patients undergoing PCI with DES.