Abstract Anemia is common amongst patients undergoing percutaneous coronary intervention (PCI) and current guidelines fail to offer recommendations for its management. This review aims to examine the relationship between baseline anemia and mortality, Major Adverse Cardiovascular Events (MACE) and major bleeding in patients undergoing PCI. We searched MEDLINE and EMBASE for studies that evaluated mortality and adverse outcomes in anemic and non-anemic patients who underwent PCI. Data were collected on study design, participant characteristics, definition of anemia, follow up and adverse outcomes. Random effects meta-analysis of risk ratios was performed using inverse variance method. A total of 44 studies were included in the review with 230,795 participants. The prevalence of baseline anemia was 26,514/170,914 (16%). There was an elevated risk of mortality and MACE with anemia compared to no anemia pooled RR 2.39 (2.02-2.83), p<0.001 and RR 1.51 (1.34-1.71), p<0.001, respectively. The risk of myocardial infarction and bleeding with anemia compared to no anemia was elevated, pooled RR 1.33 (1.07-1.65), p=0.01 and RR 1.97 (1.03-3.77), p<0.001, respectively. The risk of mortality per unit incremental decrease in hemoglobin(g/dl) was RR 1.19 (1.09-1.30), p<0.001 and the risk of mortality, MACE and re-infarction per 1 unit incremental decrease in hematocrit(%) was RR 1.07 (1.05-1.10), p=0.04, RR 1.09 (1.08-1.10) and RR 1.06 (1.03-1.10), respectively. The prevalence of anemia in contemporary cohorts of patients undergoing PCI is significant and is associated with significant increases in post procedural mortality, MACE, re-infarction and bleeding. The optimal strategy for the management of anemia in such patients remains uncertain.