Anthropogenic release of heavy metals into the environment has resulted in a continuous buildup of metals in agricultural soils. On the one hand, uptake of metals by crop plants may lead to human health risks due to food chain transfer, and on the other, leaching of metals with deep seepage may cause groundwater contamination. Soil pollution by arsenic has become one of the major environmental problems due the increased release into the environment and the high toxicity to plants, animals and humans of this metalloid. Soil is an important sink for arsenic compounds, and while arsenic uptake by most plants is low, export into waters by leaching and transport with erosion is a serious problem. Thus, an improved understanding of arsenic behavior in soils is an important environmental issue. The objectives of this study were to assess the mobility of As under two common crop plants with different rooting systems, i.e. wheat (Triticum aestivum), which has fibrous roots, and safflower (Carthamus tinctorious), which forms a taproot system, in the arid calcareous soils of Isfahan, Central Iran. A column experiment was conducted with soil monoliths (Typic Haplocalcid) extracted from a wheat and a safflower field located in the same unit of soil type. The top 10 cm of half of the columns were contaminated with As, achieving a total concentration of 23.5 mg kg-1. The background concentration was 7.7 mg kg-1. Half of the contaminated and uncontaminated columns were planted with wheat and the other half with safflower, according to their previous cultivation history. Leachate was collected continuously over the duration of the leaching experiment (86 days). After harvest, soil samples were collected at 10-cm intervals and analyzed for DTPA-extractable As by ICP-OES and for total As by XRF. Arsenic leaching was significantly increased by the contamination of the topsoil. Concentrations in discharge from contaminated fallow columns averaged 11.5 μg l-1 as compared to 6.3 μg l-1 from uncontaminated columns. Plants strongly enhanced the displacement of As into the subsoil as well as leaching. As concentrations averaged 28.8 ug l-1 in discharge from planted columns with contamination and 7.7 μg l-1 in discharge from planted columns without contamination. Safflower resulted in larger As concentrations at deeper depths than wheat. Although discharge was reduced in presence of plants due to transpiration, total amounts of As leached were larger in planted than fallow treatments. Previous cultivation history had no effect, as As displacement was the same in fallow wheat and fallow safflower soil columns. Keywords: As leaching, calcareous soil, arid climate conditions, safflower, wheat.