Compliance is a major determinant for allergy treatment, especially in children. Sublingual immunotherapy (SLIT) is self-managed at home, and no quantitative data on pediatric adherence are available. We studied the compliance in a large real-life setting. A simplified schedule of SLIT was used, consisting of a 10-day updosing phase followed by maintenance treatment in monodose containers to be taken daily (SLITOne). Italian specialists throughout Italy assessed the compliance in children who were newly prescribed SLIT according to guidelines. Parents were contacted with unscheduled telephone interviews at the third and sixth month of therapy and asked to count at that moment the remaining vials. Data from 71 children (38 boys, age range 2-13 yr) were enclosed in the database. Thirty had rhinoconjunctivitis, four asthma and 37 rhinoconjunctivitis + asthma. SLIT was prescribed for: mites in 57 (81%) subjects, grasses in 11 (15%) and 3 (4%) grass + olive mixture. Compliance data were available for all children at 3 months, and for 56 at 6 months. At 3 months, 85% of subjects had a compliance rate >75% (69% of them adhered >90%). At 6 months, 84% had a compliance rate >75% (66% of them adhered >90%). In four cases SLIT was discontinued for economical reasons, and in one case (1.4%) for side effects probably related to therapy. These data obtained in a quite large sample of children and in real-life confirm that the compliance with SLITOne is good, despite the therapy managed at home.