One of the primary processes controlling the accumulation of soil organic carbon within mineral horizons is the adsorption of dissolved organic carbon (DOC). Studies designed to relate soil properties to the adsorption capacity of forested mineral soils are limited. Thus, adsorption isotherms have been developed for 61 soils, representing five soil orders, collected from across Canada. A non-linear isotherm approach was used to derive sorption characteristics such as the desorption term (b), the point where adsorption and desorption processes are at steady state, known as the null point (np), the slope of the non-linear regression when the starting concentration is 10 mg C/L (m10), and the adsorption capacity at a starting concentration of 60 mg C/L (RE60). Soils with the strongest ability to retain DOC (RE60 > 20 mg C/L) include highly weathered soils from Vancouver Island, and B horizons of Podzols. The strongest control on DOC adsorption (RE60) was citrate extractable Fe (R2=0.61, p<0.01) and oxalate extractable Al (R2=0.59, p< 0.01). While the strongest predictor for the np of B horizon soils was effective cation exchange capacity (ECEC), and soil pH. Soils with high levels of soil organic matter (> 4%), and low soil pH showed the greatest desorption potential (b). Clay content was correlated to ECEC (R2=0.20, p =0.0002), however numerous clay soils with low levels of extractable Fe and Al displayed weak sorption characteristics. These findings support previous findings that the most important source of charge for DOC adsorption is Fe and Al oxides and hydroxides. However, this study did not find clay content to be a strong predictor of adsorption. In addition, this study did not find soil organic matter as a hindrance to adsorption processes, however soil organic content did increase the desorption potential.