Background: the intravascular ultrasound (IVUS) is an invasive access technique that allows analysis of characteristics (qualitative and quantitative) of coronary atherosclerosis. Percutaneous coronary intervention (PCI) of complex lesions (i.e., American College of Cardiology/ American Heart Association class type C) remains challenging and the outcome may be compromised. The use of intravascular ultrasound (IVUS) to guide PCI was suggested to improve outcome. The Objectives: aim of this study wasto compare intravascular ultrasound-guided and angiography-guided Intervention for Type C coronary lesions regarding major adverse cardiac events (MACE). Patients and Methods: Our study was conducted on patients undergoing elective PCI for type C coronary lesions in Cardiology Department in Ain Shams University hospitals. The study included 50 patients who underwent IVUS guidance PCI for Type C lesions and 50 patients who underwent only angiographic guidance PCI for Type C lesions. We evaluated the impact of IVUS guidance on clinical outcomes of patients undergoing PCI for complex lesions defined as ACC/AHA type C. Major adverse cardiovascular events (MACE), a composite end-point of all-cause mortality, Q-wave myocardial infarction and target lesion revascularization, were compared between the 2 groups. Mean follow-up duration was 12 months. Results: baseline clinical characteristics were similar in both patient groups. Adding IVUS to the procedure lengthened the procedure time. On the other hand, lower amount of radiographic contrast was required in the IVUS guided group during the procedure. Regarding the target coronary vessel in our study was similar in both groups with no significant difference. In addition, the number of ostial, proximal, mid and distal lesions was similar between the two studied groups. Patients with IVUS-guided PCI underwent more direct stenting, more postdilatation, larger maximal stent diameter and greater number of implanted stents. Consequently, the final diameter stenosis was significantly better in IVUS guided group. A strategy of routine IVUS for drug-eluting stent implantation in complex coronary lesions did not improve the 1-year MACE rates. Conclusion: use of intravascular ultrasound (IVUS) is associated with lower amount of radiographic contrast used during the procedure, more procedural time, more post dilatation and less postintervention final diameter stenosis. In addition, use of intravascular ultrasound (IVUS) in complex lesions allows proper assessment of minimal lumen area, optimizing PCI procedures and confirming stent well apposition.