All of the classical, old coral diseases, such as Black Band Disease (BBD), White Band Disease (WBD), Tissue Bleaching (TBL), Shut-Down-Reaction (SDR), Lobophora variegata (LOB), and others, were observed in both Atlantic and Indo-Pacific zoogeographic areas. Within a time-span of about thirty years they were registered in many locations of the Western Atlantic, from Bermuda in the North, throughout the Caribbean Sea, to Panama in the South. In the Indo-Pacific they were found in the Red Sea, Seychelles, Mauritius, Philippines, Papua New Guinea, and Australia. The newer, recently discovered syndromes appear to be more restricted : Pneophyllum conicum (PNE), a coral-killing red alga occurs throughout the Indo-Pacific in moderate quantities, but was recently observed to destroy an entire reef-crest area in Mauritius. Another new Corallinacea, Metapeyssonnelia corallepida (PEY), destroying corals in a very similar way, has so far been documented in Caribbean waters only. The first coral-killing ciliate, however, Halofolliculina corallasia (SEB), was found to be restricted to the Indo-Pacific zoogeographic region. Future field-research will show whether these geographic limitations are real, or rather artefacts of insufficient observation time.