This study was part of a three-year (2004-2007) project entitled Assessment and reduction of heavy metal inputs into Finnish agro-ecosystems that was funded by the Ministry of Agriculture and Forestry in Finland. The aims of the project were to clarify: 1) aqua regia extractable trace elements in Finnish cultivated soils with the international standard method at a national level; 2) aqua regia and AAAc-EDTA extractable trace elements in the top- and subsoil of Finnish arable land at selected crop and dairy farms; and 3) field mass balances of trace elements on the same selected crop and dairy farms at the farm level. The main aim of this study was to estimate field balances of trace elements at the farm level on typical crop and dairy farms in Finland in 2004. The trace elements studied were arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), vanadium (V) and zinc (Zn). Five crop farms were selected from southwestern Finland that is typical of arable farming and five dairy farms from Ostobothnia that is typical of milk production. For balance estimations data on the amounts of agricultural production resources imported to the farm and products exported from the farms were collected. Samples from fertiliser products, commercial feeds, crop plants, milk, meat and manure and also from top- and subsoil were collected and analysed for the ten trace elements. The soil type on the crop farms was clay and dairy farms finesand. Balance calculations were made with two models. The conventional field balance model called RAKAS-model was used for all the elements studied here and the European AROMIS-model for Cd, Pb, Cu, Cr, Ni and Zn. The main RAKAS-model used the leaching figures measured in Nordic countries and the AROMIS-model used the leaching figures measured in other parts of Europe. Erosion was taken into account in the RAKAS-model, but not in the AROMISmodel. The AROMIS-model was able to estimate internal flows of the trace elements in homegrown feeds and manure as well as the inputs of the trace elements from unidentified sources on the dairy farms. Field balances estimated at the farm level showed that the balances of the harmful heavy metals, Cd and Hg, were often slightly positive leading in accumulation of these metals into the soil on the crop and dairy farms. Selenium indicated a highly positive balance resulting in enrichment of this element in the soil in both farming systems. Also, the Cu and Zn balances were positive on the dairy farms but on the crop farms, clearly negative showing a depletion trend in the soil. In general, inputs and outputs of As, Cr, Ni, Pb and V were rather well balanced. However, if steel slag was used on the farm, accumualtion of V into the soil was even 400 times that on the farm not used steel slag.