Introduction: Respiratory allergies are becoming increasingly frequent, especially based on studies of asthma and rhinitis. It is estimated that 20-30% of the world's population is affected. Allergic reactions are caused by the production of IgE antibodies specific to inhaled allergens, such as fungi in the air. This study aimed to analyze the level of specific IgE against airborne fungi in patients with a clinical diagnosis of asthma and rhinitis/sinusitis. Methods: In total, 158 patients enrolled in the Program of Support for Asthmatic Patient, and 20 controls were studied. Clinical data from the period of 2007-2008 were surveyed using a protocol form. ELISAs were performed to quantify the levels of total and specific IgE. Results: Of the 158 patients diagnosed with asthma, 71 had rhinitis and 32 had sinusitis. There was a predominance of females and residents of urban areas. The main symptoms reported were dyspnea, cough, wheezing and nasal obstruction. There was a statistically significant relationship between dyspnea and seropositivity for Fusarium (p = 0.01) and Penicillium (p = 0.005) and between cough and seropositivity for Aspergillus (p = 0.007). Conclusions: Anti-Penicillium (79.7%) and anti-Fusarium IgE (77.8%) were found to have the highest prevalence of seropositivity in individuals with asthma and rhinitis/sinusitis. Sensitivity to fungi was higher in symptomatic individuals. The identification of environmental fungi is essential for the diagnosis of respiratory allergy.