In Finland, steel slags are used in agriculture as liming agents and fertilizers. Steel slags fulfil the quality requirements set by the Finnish fertilizer law. As more attention is paid to the safety and healthiness of food it is important to know how different factors affecting the production chain including fertilizer and liming agents affect the endproduct. In 2009, MTT Ruukki investigated the effect of steel slags on the content of chromium and vanadium in soil, potato leaves, roots and tubers. The study was carried out as pot experiments in the greenhouse using steel slags from Rautaruukki corporation s steelworks in Raahe. Two different rates (5 and 10 t/ha) of steel slags normally used in potato production were compared to a 10-fold rate (50 t/ha) and to an untreated control (0 t/ha). Medium fine sand with low or high organic matter content was used as growing medium. Potatoes of cultivar Fambo were planted in pots in January-February 2009 and grown to maturity. Steel slags used at the rates of 5 and 10 t/ha did not significantly increase the concentration of chromium and vanadium in soils. However, the 10-fold compared to the normal basal rate (50 t/ha) increased the vanadium content in both soils. The level of Cr(VI) was under detection limit in all soils. The rates of steel slag normally used in potato production did not affect chromium and vanadium contents in potato tubers, leaves and roots. The chromium and vanadium contents in potato roots were considerably higher than those in leaves and tubers. This study indicates that chromium and vanadium taken up by potato remain mainly in roots and are not transported to tubers and leaves to a great extend. Chromium and vanadium contents in tubers did not exceed the risk levels for human even with the highest rates of the steel slags used. Steel slag did not affect the silicon content of potato leaves.