Copper is a nutrient known for its lack of mobility in soils. This phenomenon affects fertilizer product and placement options when attempting to correct Cu deficiencies. A column experiment was designed to directly compare the mobility of Cu sulphate (CuSO4 5H2O) and a chelated Cu fertilizer (CuEDTA) in five soils with different levels of organic matter (2 to 108 g kg-1 organic C) and clay (4.1 to 34.9%). The movement of Cu, supplied as Cu sulphate and CuEDTA, through a 10- cm column of soil was examined during a 10-d period by monitoring the Cu concentration in leachate following daily additions of 2 cm deionized water and subsequently assaying the soil columns, in 1-cm increments, for DTPA-extractable Cu (DTPACu). Copper sulphate was virtually non-mobile in all soils with at least 20 g kg-1 organic C and 10% clay. However, in a soil with 2 g kg-1 organic C and 4% clay, Cu sulphate moved as much as 7 cm. The restricted mobility of Cu sulphate in all but one soil in this study suggests that in most western Canadian Prairie soils, having relatively high levels of organic matter and clay, Cu supplied as Cu sulphate should be regarded as immobile from an agronomic perspective. In contrast, a portion (2 to 46%) of the CuEDTA moved through the entire 10 cm column of all soils within 3 d, i.e., following three daily additions of 2 cm of water. The enhanced mobility of the chelated Cu is of agronomic significance in that it suggests that this Cu source is more likely to move into the root zone without incorporation and provide adequate feeding sites for a crop when placed in or near the seedrow. Key words: Cu mobility, Cu sulphate, Cu chelate, soil texture, organic matter, leachate