| RBC – Red Blood Cells | WBC – White Blood Cells |
| Red blood cells are called as Erythrocytes. | White Blood Cells are called as Leucocytes or Leukocytes. |
| RBCs are shaped as bi-concave discs. | These have an irregular shape. |
| Size varies from 6 – 8 µm in diameter. | Size varies from 12 – 17 µm in diameter. |
| These cells have a lifespan of about 120 days. | These have a lifespan of around 13-20 days after which, they are destroyed in the lymphatic system |
| Red blood cells do not have a nucleus at maturity. | WBCs are characterized by the presence of a large central nucleus. |
| Due to the presence of haemoglobin, these cells appear red in colour. | These cells are colourless, as they do not have any pigment. |
| Only one type of RBCs exists. | Different types of WBC’s are found in the blood such as neutrophils, B lymphocytes, T lymphocytes, monocytes, basophils, eosinophils. |
| They help in the transport of respiratory gases to different parts of the human body | They help in producing antibodies to fight against diseases causing microbes. |
| RBCs are produced in the red bone marrow | These cells are produced in the red bone marrow, lymph nodes, and spleen, etc. |
| The components of red blood cells are haemoglobin. | The components of white blood cells are antibodies with the presence of MHC (major histocompatibility complex) antigen cell markers. |
| These cells make up around 36-50% of human blood. | They make up around 1% of the human blood. |
| They are about 5 million/ mm3 of blood. | They are about 7000–8000/mm3 of blood. |
| The process of formation of RBC is known as erythropoiesis. | The process of formation of WBC is known as leukopoiesis. |
| These cells move between the cardiovascular systems. | These cells move between the cardiovascular and lymphatic systems. |
| Low count of RBCs results in Anaemia. | Low count of WBC’S results in Leukopenia. |
