Background: Slovenia is classified as being iodine-deficient. We recently found that Slovenian adolescents are iodine-sufficient (median urinary iodine concentration of the population 140 µg/l) and the prevalence of goiter is low (0.9%). The objective of this study was to evaluate iodine intake, the prevalence of marginal, low and excessive intake (<50, 50–100 and ≧300 µg/day), as well as the main sources of iodine in the diet of Slovenian adolescents. Methods: A cross-sectional study included 2,581 adolescents (1,415 girls, 1,166 boys, mean age ± SD 15.6 ± 0.5 years) representing 10% of 15-year-old Slovenian adolescents. Iodine intake was determined using a food frequency questionnaire (FFQ) in the whole population studied (n = 2,485) and weighted 3-day dietary protocols (3DPs) in a subgroup of participants (n = 191). Results: Median iodine intake determined from FFQ was 155.8 µg/day. There was no significant difference between genders. Marginal, low and excessive iodine intake was observed in 3.3, 20.3 and 11.3% of the adolescents, respectively. The major food sources of dietary iodine included table salt (39 % of the mean daily iodine intake), beverages (22%) and milk/milk products (19%). Conclusions: Dietary iodine intake in Slovenian adolescents is adequate, illustrating the effective salt iodization program.