A simple but reliable method for the determination of aluminum in serum by flameless atomic absorption spectrometry is described. By use of the Zeeman background correction, the interferences are eliminated. However, considering the numerous possible sources of contamination, extreme precautions are necessary both when taking and storing the serum. The procedures preceding the dosageper semust be minimized. The within-day and clay-to-day precision data (CV %) was 3.28 and 3.82 respectively. The average recovery for aluminum was 97.5 %. We used this method on serum from 30 healthy subjects and from 300 patients on hemodialysis. The mean aluminum concentration for the healthy subjects was 5.35 μg/l (SD ± 0.53) while the values for the hemodialyzed patients ranged from 20 to 220 μg/l.