Most diagnostic work conducted on the Taenia species zoonoses has been carried out on the larval stage of Taenia solium in man, reflecting the relative severity of the pathology caused by this stage of that organism. This review will, however, concentrate on the immunodiagnosis of the adult intestinal stages of these parasites in humans. Diagnosis of T. solium will be examined in most detail because of the relative importance of this parasite but relevant work from other cestodes of man and animals will also be discussed. In addition both classical and molecular approaches to diagnosis will be briefly covered. There have been a number of advances in immunodiagnosis of taeniasis over recent years that have improved both diagnostic sensitivity and specificity. Techniques for the detection of Taenia specific coproantigens in human taeniasis infections have been shown to more than double the numbers of T. solium cases accurately diagnosed in epidemiological studies. More recently, work on the serological diagnosis of T. solium have led to the development of a sensitive and specific enzyme linked immuno-transfer blot for the detection of species and stage specific circulating antibodies to adult worm excretory-secretory antigens. Work is ongoing to further improve these assays.