Despite the continuing developments of improved medical devices and increasing operator expertize, coronary chronic total occlusion (CTO) remains as one of the most challenging lesion subsets in interventional cardiology. Percutaneous coronary intervention (PCI) of CTO is a complex procedure carrying the risk of complications that are responsible for significant morbidity and mortality. The complications can be classified as coronary (such as coronary occlusion, perforation, device embolization, or entrapment); cardiac non-coronary (such as periprocedural myocardial infarction); extra cardiac (such as vascular access complications, systemic embolization, contrast-induced nephropathy, and radiation-induced injury). Further, certain complications (such as donor vessel dissection or thrombosis) are unique to CTO–PCI. There are also complications related to specialized techniques, such as dissection/reentry and retrograde crossing techniques. A thorough understanding of the potential complications is critical to mitigate risk during these complex procedures. © 2016 Cardiological Society of India