This activity set includes two one-page crossword puzzles about blood for a unit on blood in Human Anatomy and Physiology. There is a total of twenty-five clues that need to be solved for completion. Vocabulary terms and/or topics covered among the clues include but are not limited to: hemoglobin, hematopoiesis, antibodies, kidney, leukocyte, erythrocyte, thrombocyte, red bone marrow, phagocyte, whole blood count, leukemia, neutrophil, plasmin, albumin, macrophage, endothelium, antigens, plasma, heparin, endothelium, erythropoietin, hemophilia, macrophage, anemia, and connective tissue. The clues collectively probe students’ understanding of blood anatomy, physiology, and classification. Two one-page answer keys with a filled in template are included.