The data presented are the results of Soviet‐Polish field studies made on Hansbreen in 1989. Data from geodetic surveys show that between 1936 and 1989 the glacier retreated approximately 900 m and thinned in its lower part by an average of 50 m. Over this same period its volume shrank by 1.25 km3of ice, i.e., by 0.46 m/ yr of water equivalent. The annual mass balance of the glacier in 1988–1989 was ‐540 g/cm2; of this ‐350 g/cm2, or 65% of the total, was lost by iceberg calving. Thus in 1988–1989 the glacier lost 30.55 million m3of water, 20 million m3of which was by iceberg calving. In the year of observations the equilibrium line lay at a height of 325 m and the accumulation zone accounted for 0.53 of the total area. According to data from surface radio echo soundings 75% of the area of the glacier bed lies below sea level, at depths of up to 102 m. Three overdeepened basins were detected in the glacier bed; the intervening bars might act as stabilization levels in the course of retreat. The heterogeneous structure of the glacier, the presence of internal reflecting boundaries, and considerable differences in the velocities of electromagnetic waves between them, testify to the existence of zones of “cold”; and “warm”; ice in the complex hydrological regime of Hansbreen.