Ten easily determined soil parameters related to soil acidity were evaluated for their potential to provide simple, indirect estimates of the exchangeable aluminium percentage (PAL). These parameters were correlated with the PAL in 0.6NBaCl2extracts of soils collected from lime trials on 4 different parent materials. Six rates of lime (0, 0.75, 1.5, 3, 6, 12 t/ha) were added 3–4 years prior to collection of the samples. The soil parameters examined were the pH of soil suspensions with SMP, Woodruff and New Woodruff buffer solutions; the pH of 1, 5 and 10mMCaCl2and 0.6NBaCl2soil extracts, and the aluminium content of 1, 5 and 10mMCaCl2soil extracts. The best correlations with the exchangeable aluminium percentage for all soils considered, were those based on the aluminium content of the 5mMCaCl2extract (r=0.976, n=24) followed by the pH of the 0.6NBaCl2extract (r=0.945, n= 24). Both these methods are suggested as reliable indirect estimates of soil exchangeable alumimium percentage where availability of staff or equipment restrict direct determinations.