Several epidemiological and diagnostic studies reported increasing prevalence of allergic reactivity to fungi assessed with the use of skin testing or IgE detection. The role of sensitization to fungi in relation to the prevalence and clinical importance in atopic patients remains largely unknown. Although an allergic reaction to fungal allergens is suggested as an important contributing factor in the development of respiratory symptoms, other mechanisms, such as increased exposure to fungal metabolites, mycotoxins and other compounds of immuno-suppressant or irritant properties, may also be important. Sensitivity to fungal allergens has been recognized as a risk factor for the development and persistence of asthma, asthma severity and potentially fatal asthma exacerbations, the increased number of episodes of respiratory arrest and admissions to intensive care unit. Thus far, the role of fungi as the dominant exogenous trigger of asthma has not been completely explored. Some authors suggest, that sensitization to fungal allergens is related with specific phenotype of severe asthma. It remains to be clarified, whether this association is caused by colonization of the airways with fungi or an extreme response to exogenous spores. This review critically discusses the present state of knowledge on the prevalence of IgE-mediated allergy to fungi, as well as the contribution of sensitization to fungi to the allergic manifestations, on the basis of the recent literature. We also try to assess the importance of these connections for the future treatment of allergic disorders of the respiratory tract.