It is now 20 years since the first presentation of results from the HBV model at the Nordic Hydrological Conference in Sandefjord in 1972. Since then the use of hydrological models has grown dramatically, and today they are standard tools for an increasing number of applications. The HBV model has followed this trend, and there are examples of applications in some 30 countries. The span of applications has also widened and covers today hydrological forecasting, spillway design, studies of effects of climate change, synoptic water balance mapping, simulations of groundwater response among others. The report describes the structure of the most widely used version of the HBV modeland summarizes national and international experiences from its application.