Background Over the past decade, regulatory bodies and scientific societies recommended, as primary efficacy outcome, a score that reflects both symptom severity and use of rescue medication for clinical trials in allergy immunotherapy (AIT). Objective We sought to compare the results obtained with two subject-specific scores, the Combined Score (CS) and the Adjusted Symptom Score (AdSS), for assessment of AIT in seasonal allergic rhinoconjunctivitis due to birch and grass pollen allergens. Methods CS and AdSS were evaluated in subjects receiving a 300IR dose of allergen extract daily, by sublingual route, in four clinical trials with the 5-grass pollen tablet (NCT00367640, NCT00409409, NCT00955825 and NCT00418379) and one with the birch pollen solution (NCT01731249). The CS is derived from the Rhinoconjunctivitis Total Symptom Score (RTSS) and the Rescue Medication Score (RMS) giving equal weight to symptoms and medication use. The AdSS is a symptom score adjusting for rescue medication use. Efficacy end-points were analysed using an analysis of covariance linear model. Results In all trials, despite the different constructs of the two scores, Combined Score or Adjusted Symptom Score were similarly reduced in the 300IR group compared to the placebo group. Treatment effect was consistently demonstrated with both scores, CS and AdSS, used as either daily scores or average of the daily scores over the pollen season. Minor differences with the same statistical conclusions were observed between the results, leading to the same interpretation. Conclusions and Clinical Relevance The two scores, combined and adjusted scores, for evaluation of clinical efficacy of AIT have led to similar results, with similar statistical conclusions and similar interpretation.