Prior to the late 1980s diphtheria was regarded in many countries as one of “those rare and forgotten” diseases associated with the preimmunization era of the 1940s. Despite the success of many immunization programs, there is still much to be learned about this disease that has made a dramatic “return” in the 1990s, particularly to countries of the former Soviet Union (1 ) Since 1989, there has been a rapidly expanding epidemic of the disease in these countries, and thus has severe implications even for developed countries that have successfully controlled the disease for several decades (2 ). Diphtheria is also endemic in other countries of the world (3 ). The increase m international travel, migration from Eastern Europe, and also the emergence of “new strams” of the causative organism, Corynebacterlum diphtheria, causing disease have emphasized the importance of both clinical and laboratory-awareness. In addition, current immunization programs within each country should be reviewed, particularly for adults, to ensure that population immunity is adequate to prevent the re-emergence of epidemic disease in the Western world.