One of the commonest allergens involved in perennial allergic rhinitis is house dust mite. A good proportion of these cases prove intractable to treatment with oral and intranasal antihistamines and intranasal steroid sprays. Immunotherapy is considered a useful alternative and it helps by reducing IgE activity, suppressing helper type 2 cells and enhancing helper type 1 cells. This results in a different but ‘tamed’ response to allergens without the allergic symptoms. In this study, the role of subcutaneous immunotherapy has been assessed. In an earlier treatment, 20 patients with allergic rhinitis due to D pteronyssinus and D farinae (house dust mites) proved by positive skin prick tests, received a weekly dose of subcutaneous immunotherapy against these allergens for three years. A statistically significant reduction in symptom scores and skin prick test positivity was noted at the end of this three-year treatment period. The interesting part of this study is that at the end of 10 years following conclusion of subcutaneous immunotherapy treatment during which no further treatment was given, it was noted that both the symptom scores and skin prick positivity reduced even further from the levels at the end of the previous three-year treatment. This indicates that even after cessation of immunotherapy, improvement continues and therefore immunotherapy merits its place in the treatment of house dust mite nasal allergy.