The first cases of aluminium (Al) toxicity were reported in metal workers with apparent normal renal function. Although safety in industry has had a great improvement over the last decades, it is reasonable to think that Al workers might have a higher daily Al exposure than normal population. Therefore the aim of this study was to investigate the serum Al levels in volunteers with normal renal function, having different jobs, including people working in the main Al factory in our area. There were no significant differences in serum Al values among people working in the Al factory or in other jobs, likewise there were no differences regarding: sex, alcohol consumption, smoking habits, etc. By contrast, as we expected, urinary Al excretion was higher (p less than 0.005) in Al workers. There was a significant serum Al increase proportional to the increase of age (p less than 0.01). The known decline of renal function observed with the increasing of age and therefore the likely decrease in Al clearance, could be responsible for the serum Al increase.