OBJECTIVES: To evaluate the cost-effectiveness of a grass allergen immunotherapy tablet, Grazax (ALK-Abelló A/S) in combination with symptomatic medications compared to the standard care of symptomatic medications alone for the treatment of grass pollen induced rhinoconjunctivitis.  The analysis focuses on children, either with or without co-existing asthma, for the German setting.  METHODS: The two treatment options were evaluated in terms of costs and health outcomes using a decision tree approach.  The analysis was undertaken from the payer’s perspective, with only direct costs included in the base case.  The model followed a cohort of 1000 hypothetical children over nine years in the reference case.  Continuous use of Grazax was modelled, with the effects of treatment captured in terms of symptom management, resource utilisation and allergic asthma development.  Data inputs were drawn from published studies, databases and published clinical trials. RESULTS: The use of Grazax plus symptomatic medications compared to standard care showed an improvement in patient outcomes; 6.92 QALYs as opposed to 6.82 QALYs over the nine-year time horizon.  The total cost per patient treated with Grazax was €4117 compared to €1,502 for standard care.  The resulting incremental cost per QALY is €25,900.  The QALY gains are a result of increased quality of life related to effective symptom management and the reduction in allergic asthma development.  Sensitivity analysis carried out around key parameters shows that the results estimated by the model remain robust. CONCLUSIONS: The analysis found Grazax treatment to have an incremental cost per QALY which falls below commonly accepted willingness to pay thresholds.  Therefore, Grazax is a cost-effective option for the treatment of grass pollen induced rhinoconjunctivitis for children in Germany.