Blood transfusion is a common intervention in critically ill patients to correct anemia from primary blood losses such as trauma, surgery, gastrointestinal bleeding, and other etiologies. While it can be life-saving, it also carries some risks of developing adverse reactions. Several studies revealed an increase of morbidity and mortality following blood transfusion hence it must be done properly and according to the right indications. This literature study aims to identify the indication for blood transfusion in critically ill patients as well as the complications that may arise from it.