Both eosinophils and basophils play active pathogenic roles in the inflammation associated with allergic disorders. Both types of cells share a majority of their cell surface structures, and because of these common surface molecules, both cells can be stimulated with a single ligand simultaneously. The growth of both types of cells is controlled by IL-3, GM-CSF, and IL-5. All three growth factors are also capable of priming both eosinophils and basophils for enhanced biological functions, such as increased mediator release and prolonged survival. Both cells express beta 2 integrins, and in contrast to neutrophils, they also express several beta 1 integrins. Ligation of these adhesion molecules also transduces the intracellular signal leading to regulation of the cellular functions. In this review, we briefly describe the effects of various ligands of surface receptors and several pharmacological compounds on the functions of human eosinophils and basophils.