Allergic diseases like atopic rhinitis, bronchial asthma, and urticaria are prevalent and on the rise. Mast cells are known to play a central role in the immediate phase reaction of allergic diseases through the IgE-mediated release of a variety of chemical mediators like histamine, leukotrienes, and prostaglandins. On the other hand, T lymphocytes, basophils and eosinophils are thought to be responsible in inducing the late phase response. Yet, recent studies show that the mast cell cannot be simplistically assigned a role in the immediate phase allergic response, and that this cell plays a crucial role in ongoing allergic inflammation, including the development of hyper-responsiveness. In the present article, the author will try to discuss the integrated roles of mast cells in IgE-mediated allergic inflammation with specific emphasis on the roles of mast cell-IgE networking and mast cell-structural cell interactions in the late phase allergic response and chronic allergic inflammation.