Fifteen patients with nasal allergy, undergoing antigen-specific immunotherapy were subjected to high frequency submucosal diathermy (HF-SD) of their inferior turbinates to resolve nasal obstructions. The short-term effect of HF-SD (n=15) was 93% and long-term effect (n=10) was 70% for decreasing nasal obstruction as evaluated by severity of the symptom in allergy diary. The average score of nasal obstruction at pre-operation in allergy diaries was 1.74±0.62, whereas, the postoperative score was 0.33±0.45, 0.37±0.41, 0.41±0.39 at 6 months, 1 year, and 3 years, respectively. The postoperative airway resistance was significantly decreased to 12.87±29.81cm H₂O/L/sec compared to pre-operation, 55.27±42.81. The histological changes of the nasal mucosa after HF-SD were also investigated. Continuous histological changes in the nasal mucosa at 1 month postoperation were mainly in the connective tissue of the lamina propria. Evaluation of the results shows that HF-SD of the nasal mucosa is an effective treatment for nasal obstruction in patients with nasal allergy undergoing antigen-specific immunothrapy.