To assess apoptosis frequency in the nasal mucosa of patients with perennial allergic rhinitis. Eleven patients and five healthy subjects accepted to participate, from 10 to 16 years old. None of them had evidence of acute infectious disease, tobacco exposure or use of corticosteroids, antileukotrienes, antihistamines or immunotherapy. After a clinical evaluation and a skin prick testing, a nasal symptoms questionnaire was applied and a nasal washing was performed. Two hundred cells were examined (Giemsa and eosin yellowish) and apoptosis was identified by immunohistochemistry (Active-Caspase-3) (p20L18, sc-1225. Santa Cruz Biothecnology, Inc. Santa Cruz). The most common allergen was Dermatophagoides sp in 10 patients (91%). The total score of the nasal symptom questionnaire was 3 to 8 (median 6) in patients and 1 to 4 (median 2) in healthy subjects (p < 0.05, Mann Whitney U test). Frequency of eosinophils was 11 to 80% in patients and 0 to 1% in healthy subjects (p < 0.05, Z for proportions). Apoptosis was less frequent in patients (0 to 5, median 2) than in healthy subjects (4 to 16, median 8) (p < 0.01, Mann Whitney U test). Perennial allergic rhinitis may be associated with decreased apoptosis in the nasal mucosa.