Clinical material relevant to the emergence and resolution of a pseudocyesis during the analysis of an adolescent girl is presented. This case provides evidence that psychodynamic factors can alter human behavior, produce significant mental disturbance, and even alter physiological functions. The data not only validate the psychoanalytic approach but are relevant to its very origins. The importance of the transference neurosis and the interrelationship of oedipal and preoedipal conflicts are emphasized. A brief comment is addressed to the patient's penis envy which appeared as a secondary phenomenon.