In the determination of aluminium by atomic absorption spectrometry with a graphite furnace, coexisting oxyanion salts of alkaline earth metal enhanced the aluminium atomic absorption. The relative absorbance was increased with decreasing of the ramp atomization rate and with decreasing of the sheathing gas flow rate less than 51 min^<-1>. These results show that the enhancement effect is caused by the reductivity of the carbide of alkaline earth metal which is formed in the furnace at ashing and atomization steps. The relative enhancement followed the sequence: Ca>Sr>Mg. The addition of mixture of calcium nitrate and ammonium salt of EDTA enhanced the atomic absorption of aluminium and also removed the interference of chloride in the atomic absorption of aluminium.