The field of hematooncology comprises dozens of diagnoses. Therefore, it is not possible for a single person to study and deeply understand all relating problems. At our department, we have established several working groups that concentrate on separate hematological diagnoses, i.e., leukemia, lymphoma, myeloma, and transplant groups. Members of these working groups also prepare the diagnostic and therapeutic standards for all basic hematooncological diagnoses. Thus, we can, within our clinic, achieve high-quality and fundamental knowledge necessary for solving the problems arising during the diagnostics and treatment of our patients. Within the framework of working groups, research projects aimed at specialized problems are also performed. Working groups present their results regularly at the lectures organized by our department, domestic and international conferences and workshops, as well as in Czech and international literature.