A red blood cell contains hemoglobin which allows blood to transfer the oxygens. A red blood cell count is blood test which is used by health care professional to identify the red blood cells present in an individual body. Further, red blood cell is simply called red cells or erythrocytes. The physiology process is called a function of the living organism and its parts and physical and chemical factors and processes involved. The present presentation is based on the physiological process of Red blood cells. The present research will cover the primary role of red blood cells and the physiology of blood.