The amounts of cobalt and chromium released to the saliva in individuals wearing cobalt-chromium partial dentures have been measured. Saliva was collected during a 5-min period, both with and without dentures in the mouth, and the two samples compared. More than 80% of the 30 cases showed increased amounts of metals with the denture in the mouth. Newer and larger dentures liberated more than did older and smaller ones. The median increase in chromium was approximately twice that of cobalt.