Numerous studies have reported the relation between pre-procedural C-reactive protein (CRP) levels and the risk of major adverse cardiac events (MACEs) in patients undergoing percutaneous coronary intervention (PCI). However, the results across the studies were inconsistent. The aim of this study was to evaluate the predictive effect of pre-procedural CRP levels and the risk of MACEs in patients undergoing PCI. Longitudinal studies on the association between pre-procedural CRP levels and MACEs were identified by electronic and manual searches. Summary risk ratios (RRs) and 95 % confidence intervals (CI) were calculated employing an inverse variance random-effects model irrespective of between-study heterogeneity. Thirty-three studies involving 34,367 patients with 4119 MACEs were included in this study. High CRP level was associated with increased incidences of MACEs, all-cause death, myocardial infarction, coronary revascularization, and clinical restenosis, with pooled RRs of 1.97 (95 % CI, 1.65, 2.35), 2.88 (95 % CI, 2.15, 3.86), 1.81 (95 % CI, 1.48, 2.21), 1.31 (95 % CI, 1.11, 1.56), and 1.45 (95 % CI, 1.07, 1.96), respectively. Dose-response analysis showed that every 1 mg/L increment in pre-procedural serum CRP level was associated with a significant 12 % increase in the risk of MACEs. In spite of heterogeneity across the included studies, this meta-analysis suggests that pre-procedural serum CRP level is a valuable predictor of MACEs in patients undergoing PCI.