This paper reviews selected studies examining the enhancing effects of drugs and hormones on learning and memory. Many strategies have been used in an effort to dissociate drug effects on learning from drug effects on other processes affecting the performance of responses. These strategies include the use of tasks with various motivational and response requirements, the use of studies explicitly examining drug influences on performance, the use of posttraining drug administration and the use of various forms of latent learning tasks. It seems clear from these studies that the dissociation of learning and performance effects of drugs cannot rest on one task or one experiment. Overall, the evidence summarized in this paper provides strong support for the conclusion that drugs can and do enhance retention and that the effects are due to influences on memory storage rather than to other factors that influence performance.