Research in recent years has brought a wealth of information about the important role of immune suppressive myeloid cells in cancer and other diseases. There is growing evidence suggesting that the expansion of these regulatory cells may represent a common response to all forms of inflammation. Several clinical trials target these cells with the goal of improving the immune response in cancer. However, the field as well as the term ‘‘regulatory myeloid cells’’is highly controversial, and many issues remain unresolved. These issues were discussed at the international meeting in Clearwater, Florida held from March 8 through 11, 2009. Approximately 240 researchers working on myeloidderived suppressor cells (MDSC), regulatory (suppressive) dendritic cells, as well as suppressive macrophages in cancer, infectious diseases, sepsis, trauma, and autoimmune diseases convened. Participants from different fields of research were provided with the opportunity to assess the data about expansion, accumulation, differentiation, regulation, and function of immune suppressive myeloid cells within the context of immunology of cancer and other diseases.