Different extracellular signaling molecules that bind to receptors on the cell membrane use calcium ions for signal transduction. Due to the opening of receptoroperated calcium channels, some cytokine receptors and Gprotein coupled receptors induce an increase of intracellular calcium concentration upon activation. Calcium ion is a versatile intracellular secondary messenger that control many different cellular functions by changing its cytoplasmic concentration. A specific and complex network of signaling proteins recognizes intracellular calcium alterations to modulate cellular processes. Some reports have previously demonstrated that calcium also regulates hematopoiesis. This review examines the participation of intracellular calcium in hematopoiesis after the stimulus of various myeloid cytokines such as interleukin-3 and granulocyte-macrophage colonystimulating factor. In addition, the role of adenosine triphosphate and its receptors in inducing calcium increases during hematopoiesis is discussed. Lastly, the participation of this ion in myeloid proliferation and differentiation by cytokines and P2 receptors is also discussed.