Cadmium (Cd) is a non-essential toxic trace metal that can be readily taken up by plant roots and accumulate in above-ground tissue. Recent studies have reported high levels of Cd in cacao (Theobroma cacao L.) beans from Ecuador (average 0.9 mg Cd kg^-1 bean), which has raised concerns on its future trade due to difficulties to comply with food safety regulations. The problem of high Cd concentrations in cacao beans from Ecuador is unrelated to point pollution but a geogenic one, combined with cacao being a plant with high affinity for Cd uptake (Cd accumulator). Managing Cd in cacao requires an understanding of the processes affecting soil Cd bioavailability. Soil factors such as total Cd, pH and organic carbon content are the main factors explaining Cd concentration in cacao beans. Since cacao is a perennial crop with deep-rooted soil horizons it is important to understand the functionality of the root structures on Cd uptake. Here we hypothesized that the origin of shoot Cd in cacao is affected by the distribution of roots in the soil and bioavailable Cd. A pot experiment with cacao seedlings was conducted to better understand and quantify the contribution of rooted soil compartments (top-or bottom soil) on the concentration of Cd in cacao leaves using ¹⁰⁸Cd as a tracer. Pots contained superimposed soils (top and bottom) that differed in Cd availability either by liming (soil pH raised from 5.6 to 6.5) or by using soils with contrasting properties (surface soil with high Cd and subsurface soil low Cd) to evaluate its effect on Cd source apportionment. The first new leaf on each plant was harvested after 7 weeks of growth and ¹⁰⁸Cd and ¹¹¹Cd were measured by ICP-MS after nitric acid digestion. Results showed that 57% of Cd in the shoot was derived from the top soil compartment in plants grown in fully non-limed soils. When only the top compartment soil was limed, the majority (67%) of Cd in the shoot derived from the bottom compartment soil. By liming top and bottom soils, 68% of Cd in the shoot derived from the top compartment. In plants grown in two contrasting soils (surface over subsoil), about 60% of Cd in the shoot was derived from the top compartment and this fraction was observed independently if the surface top soil was limed. In contrasting soils, Cd in the shoot significantly reduced by a factor 2 when top soil was limed. Surprisingly, no significant difference in shoot Cd was observed in plants grown in surface soil with or without liming. At the conference results from 4 months growth will be presented and will be discussed with root biomass of the plants.