The International Glaciological Society will hold an international workshop on World Glacier Inventory in 2008. The workshop will be held in Lanzhou, People’s Republic of China, during 20–24 (Saturday to Wednesday) September in 2008. THEME An effort to create an inventory of important features of glaciers on a global scale was launched as part of the International Hydrological Decade (1965–1974). The main motivation was to obtain information on distribution of surface area and ice volume of glaciers. Initially it was aimed at all glaciers outside the existing two ice sheets, Greenland and Antarctica. It was also planned to repeat a similar effort every 50 years to detect changes in glaciers. To date about 37% of the estimated total glacier surface is inventoried and made available through the World Glacier Monitoring Service (WGMS) in Zürich and National Snow and Ice Data Center (NSIDC) in Boulder. In the meantime, it was realized that the original inventory method was too time consuming, and some areas even lacked the information necessary for the inventory. In the early 1980s a simplified inventory method was developed mainly based on satellite images. This is outlined in Global Land Ice Measurements from Space (GLIMS) which covers 34% of the estimated glacier surface outside Greenland and Antarctica. During the 40 years after launching the World Glacier Inventory and 25 years after introducing the simplified inventory method, both efforts made substantial progress and contributed tremendously to our knowledge in glaciology and related sciences. They are, however, not complete. The original and detailed inventory was completed by only 11 countries and one region. Viewed globally, some 63% of the estimated total surface area remains untouched. Some completed national inventories are not forwarded entirely to the world data centres. The satellite-based inventories also left 66% uncovered, although some areas are covered by both methods. Combining both inventories, 45% is dealt with, leaving 55% of glacier surfaces inaccessible. Curiously 26% of glacier surfaces is inventoried by both methods. This situation offers a chance to compare simplified methods with the original method, in order to estimate the quality of the satellite-based and semi-automatic inventory methods. Further, original and simplified methods were successfully applied beyond the regions of the original concept, namely to Greenland and Antarctica, albeit for limited areas. A number of scientific works have been already accomplished by using inventoried data. Glacier inventory is often used to calculate changes in hydrological basin discharge. The combination with GCMs provided scenarios on future changes of the sea-level. These works have not, to date been discussed among related communities. Glaciers in certain geographic regions are inventoried but the resulting files were not always forwarded to data centres. Although not in the original plan, some areas in Greenland and Antarctica were inventoried, but data were not sent to the world data centres. All these problems make the estimation of the ice volume, a primary goal of the inventory effort, difficult. In the meantime the cryosphere itself is rapidly changing. It is of the utmost importance to complete the global inventory as soon as possible. The proposed workshop is not an occasion to present the inventoried contents. The workshop is intended to review and discuss what has been accomplished on a global scale, and to consider how WGI data have been and will be applied and what remains to be done to complete the WGI.