A spectrophotometric method is described for the determination of aluminium in sodium dithionite extracts of soils using catechol violet (CV) at wavelength 585 nm following nitric/sulfuric acid digestion and neutralization. The detection limit is 5 mg/kg Al in soil. Evaluations undertaken were: contributions to blank value of digestion and neutralization reagents; interferences from iron; effects of storage of acid digests; and stability of sodium dithionite extracts. All digest and neutralization reagents contributed to the blank value with lowest values found for ultra‐pure neutralizing reagents. Soil extracts were stable for up to 90 days when stored at 4°C and ‐12°C.