What is the difference between pediatric oncology and hematology?

See below.: Hematology is the study of blood disorders, things like clotting disorders, red blood cell disorders, bleeding disorders. Oncology is the study of cancer. These two overlap when dealing with leukemia (cancer of blood cells) and lymphomas.

Different focus.: Pediatric oncologogists diagnose, treat and care for children with cancer or malignancies. Some overlap with hematology because they are blood cancers. Pediatric hematologists deal with many blood problems, some which are cancers (leukemia), some which are minor (iron deficiency anemias), some which are life-threatening (aplastic anemia), some which are inherited (sickle cell, hemophilia).

Different patients: Oncology is the care of cancer patients. Hematology is the care of patients with blood disorders. Most pediatric hematologist-oncologists treat both groups of patients, as the board certification in pediatrics is for both hematology and oncology.