['Recent observations, especially in adults, suggest that asthma severity may be associated with fungal sensitization. Other studies suggest that some patients with severe asthma and fungal sensitization may benefit from anti-fungal therapy. Currently, the prevalence of fungal sensitization among children with severe asthma is not well characterized.', 'We determined prevalence of fungal sensitization among children with moderate to severe persistent asthma and compared clinical characteristics between sensitized and non-sensitized children, including asthma severity, serum immunoglobulin E, and pulmonary function.', 'Of the 64 children enrolled, 25 (39%) had evidence of sensitization to one or more fungi. Nineteen of 25 (76%) children with fungal sensitization were categorized as severe persistent compared to 13 of 39 (33%) children without evidence of fungal sensitization (odds ratio = 6.33, 95% confidence interval 2.04-19.68, P = 0.0014). Of 32 severe persistent asthmatics, 19 (59%) demonstrated evidence of fungal sensitization. Serum immunoglobulin E was significantly higher (P < 0.001), and pulmonary function (including FEV1, FEV1/FVC, and FEF25-75%) significantly lower in the fungal-sensitized patients (P = 0.016, 0.0004, and 0.002, respectively). Bronchial biopsy of sensitized children revealed basement membrane thickening and eosinophil infiltration.'] Is fungal sensitization in childhood persistent asthma associated with disease severity?