AbstractSeveral glycoproteins that control blood formation have recently been characterized. Through their overlapping, synergizing, and antagonistic effects, they regulate hematopoiesis in a highly differentiated network. Large scale production of these colony stimulating factors (CSFs) has been made available by recombinant DNA technology, and a series of clinical studies in a variety of indications has been finished. In general, the subcutaneous application seems to be superior to the intravenous injection and causes less toxicity. Erythropoietin has been shown to be a highly effective treatment for anemia in patients with chronic renal failure. Granulocyte colony stimulating factor and granulocyte‐macrophage colony stimulating factor are capable of ameloriating the chemotherapy induced neutropenia, and to abbreviate the time span of myeloaplasia after bone marrow transplantation. The potentials of other colony stimulating factors like Interleukin 1 and Interleukin 3, and combination regimens of several CSFs will be discussed. © 1992 Wiley‐Liss,