Under conditions of food deprivation, relative to the equivalent satiation condition, increases in the self-administration of d-amphetamine in three out of three monkeys, of cocaine in two out of three monkeys, and of nicotine in one out of three monkeys, were observed. Furthermore, these increases were dose-dependent, i.e. with low doses there were large increases in number of infusions, but with high doses there were no differences in number of infusions between the two feeding conditions. For some doses of diazepam there were increases in number of infusions under the deprivation condition relative to the satiation condition, but these increases were not statistically significant. In contrast, food deprivation produced slight, but significant, increases in the number of perphenazine infusions in one monkey but inappropriate level responses were also high for this monkey as well. In most cases, increases under food deprivation occurred with drugs that already maintained responding above saline under satiation conditions. Therefore, food deprivation does not appear to convert non-reinforcers into reinforcers, but instead increases intake of drugs that function as reinforcers. This effect may contribute to the persistence of psychomotor stimulant drug-seeking behavior in humans.