The red blood cell distribution width (RDW) is a simple, low-cost biochemical parameter that reflects the level of anisocytosis as determined by a typical complete blood count. Anemia and other inflammatory disorders are diagnosed using RDW and other haematological parameters. Higher RDW levels have been implicated in numerous recent studies as a potent independent predictor of morbidity and mortality in a variety of cardiovascular diseases (CVDs). Therefore, RDW may be crucial in determining the severity and development of CVDs. In this review, we have outlined the mechanisms underlying the link between RDW and CVDs, as well as a few literature reviews that explain RDW and related CVDs, which demonstrated that even a 1SD increase in RDW causes various CVDs such as heart failure (HF), myocardial infarction (MI), atrial fibrillation, atherosclerosis, hypertension, and stroke depending on the degree of involvement. To varying degrees, some common mechanisms that contribute to increased RDW include oxidative stress, inflammatory cytokines, anemia, lipid abnormalities, vitamin D-3 deficiency, glycemic disturbance, chronic kidney disease (CKD), and liver disease. Finally, it can be concluded that even a 1SD change in RDW can indicate a significant risk of a CV event.