Background: The guideline recommended strict blood pressure (BP) control for the patients treated with percutaneous coronary intervention (PCI). We aimed to evaluate the relationship between mean observed BP and long-term outcomes for patients with or without lesion complexity. Methods: A total of 1,470 patients who underwent PCI were investigated. We categorized the study population into four groups based on mean observed BP and lesion complexity (left main & three-vessel disease, chronic total occlusion, total stent length ≥60mm, or bifurcation two stenting): Group A (non-complex & systolic BP ≤120mmHg, n=310), Group B (non-complex & systolic BP >120mmHg, n=674), Group C (complex & systolic BP ≤120mmHg, n=131), and Group D (complex & systolic BP >120mmHg, n=355). We evaluated major adverse cardiovascular and cerebrovascular events (MACCEs), defined as cardiac death, myocardial infarction (MI), repeat target vessel revascularization, or stroke. Results: Well-controlled BP group (Group A&C) showed significantly lower systolic BP than uncontrolled BP group (Group B&D) (114.3±6.1mmHg vs. 130.7±7.6mmHg, p<0.001). MACCEs occurred less frequently in Group A (18.9%) than Group B (23.6%), Group C (22.7%), and Group D (33.6%) (p=0.001) at 8 years. After multivariate analysis, with Group A as a reference, the adjusted hazard ratio (HR) for MACCEs was 1.382 (95% confidence interval [CI] 0.978-1.954, p=0.067) for Group B, 1.559 (95% CI 0.957-2.540, p=0.075) for Group C, and 1.872 (95% CI 1.296-2.705, p=0.001) for Group D. In Cox regression model, although lesion complexity was not associated with MACCE, systolic BP≤120mmHg was an independent predictor for reduced rate of MACCE (HR 0.667, 95% CI 0.485-0.918, p=0.013). Conclusions: Mean observed systolic BP ≤120mmHg after PCI was independent predictor for reduced MACCEs regardless of lesion complexity. Key Words: Blood Pressure; Percutaneous Coronary Intervention; Lesion Complexity; Treatment Outcome