AbstractConditioned responses to amphetamine treatment at three doses were investigated with the “conditioned emotional response” paradigm, in which an auditory‐visual stimulus was presented 3 min before i.p. drug injection to rats lever pressing for food pellets. Conditioned responses to this preinjection stimulus were indicated by changes from baseline response rate during each of eight conditioning sessions and after water injections (again preceded by the A‐V stimulus) on a final extinction‐test day. In experiment 1, the reinforcement schedule was tandem VI‐30 sec/FR4, and the amphetamine dose was 3.0 mg/kg, which produced nearly complete response suppression by the end of the 20‐min postinjection period. Suppression to the preinjection CS was seen after two conditioning sessions, and marked condition suppression also occurred after water injection on the test day. In a second experiment, using additional animals, the reinforcement schedule was VI‐60 sec, and two drugged groups were used to determine lower‐dose amphetamine effects. Significant preinjection suppression (of a lesser degree than seen in experiment 1) developed after six conditioning sessions with amphetamine 1.5, but not 0.8 mg/kg. Similar dose differences were seen in the postinjection‐conditioned responses. These results provide dose‐response information on conditioned responses to a CNS stimulant in the conditioned