ABSTRACTBoth the aims of investigations, and the characteristics of the results obtained, of changes in mass balance of whole glaciers, occupying clearly-defined drainage basins, are assessed in the context of questions concerning the role of glaciers in the basin hydrological cycle.The range of detailed mass balance data collected since 1945 is considered in terms of length and continuity of record of changes in ice storage, geographical distribution of basins with respect to the various mountain ranges and climatic regions of the world, and whether the glacierised basins are also subject to measurements of meltwater runoff and water balance.Results of ice balance determinations are available for 95 glaciers, from all major ranges with the exception of the Andes. Of these glaciers, 80 per cent are smaller in area than 10 km2. Eleven records are for periods of twenty or more years, but the glaciers with the longest records are spatially clustered particularly in Scandinavia, the European Alps, and north-western North America. In 25 of these glacierised basins, measurements of discharge have accompanied those of mass balance, but full water balance determinations with continuous monitoring of precipitation and discharge are limited to 11 basins. Records of water balance generally refer to shorter periods than those of ice balance. Although the hydrological method of determining mass balance produces results which differ from those derived from the more commonly-used glaciological method, it provides information more useful for hydrological and water resources purposes. Continuous hydrometric data also give an indication of the influence of hydrometeorological conditions on sequential changes in the mass of stored water and on temporal variation of runoff.Long term acquisition of simultaneous mass and water balance data for individual basins remains necessary in order to allow assessment of the impact of climatic shifting on both glacier mass balance and montane runoff.