We have evaluated the efficacy of oral immunotherapy in 34 patients affected by seasonal allergic rhinoconjunctivitis due to grass pollen. Diagnosis was performed on the basis of medical history, Skin Prick Test and Rast and the mean duration of the disease was 6 years. The treatment started in November and consisted of increasing daily doses of allergen; when the maximum dose was reached, it was continued twice a week till April. After two years of treatment we observed a statistically significant reduction in the severity of the symptoms considered and in the amount of oral antihistamines taken during the pollen season. The treatment was well tolerated and patients did not experienced any adverse effect. We therefore conclude that oral immunotherapy is a valid alternative to traditional subcutaneous immunotherapy in the treatment of seasonal allergic rhinoconjunctivitis due to grass pollen.