Hone your clinical reasoning and diagnostic skills with a new series of case-based topic-specific studies. This compilation of 20 hematology/oncology cases from Pediatrics in Review was curated to help clinicians keep an open mind when seeing patients and maintain a broad index of suspicion for hematologic and oncologic disorders. Featured cases cover some aspects of the 2024 Content Outline of the American Board of Pediatrics content areas of bleeding disorders with both congenital and acquired disorders represented; disorders of white blood cells both quantitative and qualitative; hemoglobinopathies, focusing on more unusual presentations of complications; anemia, both productive and destructive processes; and finally oncologic disorders, including unusual presentation of childhood leukemia and solid tumors. This set of cases is a useful adjunct for those participating in Maintenance of Certification or preparing for initial certification.