Leukemia is a neoplasia of the hematopoietic and lymphatic system with an abnormal increase of immature blood cells. Besides a wide range of systemic symptoms there are also oral manifestations. They include petechiae, ulceration, mucosal bleeding, swelling and redness of the gingiva and enlarged lymph nodes. Secondary complications due to the reduced immune system like candidiasis, periodontal bone loss etc. may occur.