Vegetables enriched with iodine can become an alternative to iodized salt as a way of introducing this element to human diet. Iodine is not a nutritional element for plants. Its influence on biochemical and physiological processes occurring in plants, including mineral nutrition, has not yet been diagnosed. In the available literature, no information can be found on the comparison of iodine biofortification efficiency of carrot storage roots through soil fertilization and foliar nutrition. The aim of this study was to assess the influence of pre-sowing soil fertilization with iodine (in the form of KI) and foliar application of this element (as KIO3) on the biofortification effectiveness and mineral composition of carrot storage roots. Carrot cv. Kazan F1 was cultivated in a field experiment in 2008 and 2009. The experiment comprised different variants of soil and foliar application of iodine: control (without soil or foliar application of iodine), combinations with pre-sowing soil fertilization with iodine in the dose of 0.5, 1.0 and 2.0 kg I ha–1 as well as foliar nutrition with iodine in the concentration of: 0.0005%, 0.005% and 0.05% repeated four times. In total, using 1,000 dm3 of work solution per 1 ha, the following amounts of iodine were applied to plants in the latter variant: 0.02, 0.2 and 2.0 kg I ha–1, respectively. In carrot storage roots, iodine as well as P, K, Mg, Ca, S, Na, B, Cu, Fe, Mn, Zn, Mo, Al, Cd and Pb were analyzed with the ICP-OES technique, whereas nitrogen was determined with Kiejdahl’s method. In all the tested combinations, significant increase in iodine concentration in carrot was observed versus the control (2.1 mg I kg–1 d.w). Storage roots of carrot treated with the highest doses of iodine (through soil and foliar application) contained comparable amounts of this element: 10.2 and 8.6 mg I kg–1 d.w., respectively, which were also the highest quantities relative to the control and the other treatments. Soil fertilization in the dose of 1.0 and 2.0 kg I ha–1 as well as foliar nutrition with 0.0005%, and 0.05% solution of iodine contributed to an increased content of nitrogen in carrot roots. Soil and foliar application of iodine, in relation to the control, resulted in a higher content of Mg, Fe, Al and K as well as a lower S concentration in carrot, except K and S in the combination with soil fertilization of 0.5 kg I ha–1. Diversified influence of the iodine dose, form and application method was observed in reference to concentrations of: P, Ca, Na, B, Cu, Mn, Zn, Cd and Pb in carrot storage roots. Iodine treatments included in the research had no significant influence on the Mo content in carrot.