Linear sweep cathodic stripping voltammetric methods were modified to measure labile and total concentrations of Fe3+and Zn2+in the nanomolar range in soil solutions. Labile concentrations of Fe (25–220 nmol/L) and Zn (37–208 nmol/L) were measured in 0.5 mL aliquots of filtered (0.4 μm) distilled water extracts (solution:soil ratio= 1) of four agricultural soils. After decomposition of complexed forms of the metals by evaporation of the solutions in HNO3, total soluble Fe and Zn were measured. Labile Fe comprised approximately 1% of total soluble Fe, while labile Zn comprised 13–43% of total Zn in the four soil solutions. The methods provide a linear range of 5 ‐100 nmol/L and sufficient precision to detect concentrations of labile and total Fe and Zn likely to occur in soil solutions.