Abstract Objective To investigate the iodine status of schoolchildren in the Principality of Liechtenstein. Design A representative, cross-sectional principality-wide screening of iodine level in household salt and urinary iodine concentrations (UIC) in primary-school children. Data were compared with the WHO criteria and with 2009 iodine survey data from Switzerland, a neighbouring country that supplies most of the salt used in Liechtenstein. Settings Principality of Liechtenstein. Subjects Schoolchildren (n 228) aged 6-12 years from five different primary schools representing 11·4 % of the children at this age. Results The median UIC was 96 (range: 10-446) μg/l; 11 %, 56 % and 1 % of children had a UIC 300 μg/l, respectively. In all, 79 % of households were using adequately iodised salt (≥15 ppm). The median UIC was 20 % lower than that in children at comparable age in Switzerland (120 μg/l; P < 0·05). Conclusions According to the WHO criteria, schoolchildren in Liechtenstein are mildly iodine deficient and household iodised salt coverage is inadequate. Public health measures to increase iodine intakes in the Principality should be considere