Psychoanalysis has been criticized for its lack of a quantitative research tradition and its resulting reliance on the case history method for its data. While the in-depth observation of a small group of cases has an important place in the development of science, particularly in the hypothesis generating phase, it is argued that the testing of psychoanalytic hypotheses must depend on research methods that allow for more stringent control and replication. Five studies that utilize a true experimental design and that examine psychoanalytically significant topics are described. Special problems confronting the psychoanalytic experimenter are discussed. It is hoped that this article will stimulate those investigators who have an interest in testing psychoanalytic principles to design future studies that are rigorous in their methodology.