A flow injection (Fl) spectrophotometric procedure for aluminium (lll) determination has been develop. The method was based on complex formation of aluminium (lll) with pyridoxal salicyloyhydrazone (PHS) in an acid medium. A 75 l of 0.15% pyridoxal salicyloyhydrazone (PHS) reagent solution (PSH plus KNO3) was injected into a standard and/or sample solution carried stream with the flow rate of 2.1 ml/min and merged with a carrier stream of 0.05M hydrochloric acid with the same flow rate. The resulting yellow product was monitored at 415nm. A linear calibration curve over the range of 0.0-0.8ppm has been established. The technique was found to be reproducible, accurate, sensitive, and selective. The proposed method has been applied to the determination of aluminium (lll) in tap water samples collected from Chiang Mai University campus. The aluminium contents in water samples were found to be in the range 0.08-0.29ppm. The detection limit was 0.01ppm while the coefficient of variation was 1.83%(at 0.40ppm Al(lll).n = 12).