Eosinophilic esophagitis (EE), first recognized as a unique entity some 12 years ago, is a chronic, TH2-type inflammatory disorder of the esophagus. The diagnostic criterion is a peak infiltration of the esophageal epithelium with > 24 eosinophils/HPF. Though originally believed extremely rare, EE is increasingly recognized and its prevalence may soon equal chronic inflammatory bowel diseases. The main symptom of EE is dysphagia for solid foods with imminent risk of food impaction. Endoscopic abnormalities are varied but discreet, with white exudates being the most prominent sign. Though EE likely remains restricted to the esophagus, chronic inflammatory processes may induce esophageal fibrosis. Therapeutic recommendations include systemic or topical corticosteroids, leukotriene antagonists, protein elimination diet and dilation. In EE, the inflammatory pattern consists of eosinophils, T-cells and mast cells, together with increased expression of IL-5 and TNF-α . Interestingly, clinical data as well as animal studies show a striking association of EE with allergic airway disorders. Immunologic interactions between the airways and the esophagus might be transmitted, at least in part, by IL-13. Adult EE patients are most frequently sensitized to aeroallergens, whereas in children, sensitization to food allergens is predominant. Despite enormous research effort, many crucial questions remain unsolved requiring further investigation.