Allergic asthma is characterized by a temporally and quantitatively inappropriate immunologic response. One of hallmarks of this response is the accumulation of eosinophils in the airway and lung parenchyma, which results in bronco-constriction, lung damage and ultimately fibrosis. GM-CSF plays a pivotal role in this process by modulating eosinophil function and survival. In this review, we discuss the effects and molecular regulation of GM-CSF secretion by eosinophils. Recent data demonstrate activated eosinophils release small amounts of anti-apoptotic GM-CSF by stabilizing its coding mRNA.