The International Diatom Symposium (IDS) is the main meeting for diatom researchers from all over the world. The IDS is organized every two years and its purpose is to exchange information on the ecology, taxonomy, physiology and molecular biology of diatoms and establish mutual understanding of diatom researches. By bringing together diatom researchers from various backgrounds, we hope to stimulate discussion, exchange and networking. The 23rd International Diatom Symposium will be held from September 7 to 12, 2014, in Nanjing, China, under the auspices of Nanjing Institute of Geography and Limnology, Chinese Academy of Science on behalf of the International Society for Diatom Research.