We assess the volume change and mass balance of three ice caps in southern Iceland for two periods, 1979-1984 to 1998 and 1998 to 2004, by comparing digital elevation models (DEMs). The ice caps are Eyjafjallajokull (ca. 81 km(2)), Tindfjallajokull (ca. 15 km(2)) and Torfajokull (ca. 14 km(2)). The DEMs were compiled using aerial photographs from 1979 to 1984, airborne Synthetic Aperture Radar (SAR) images obtained in 1998 and two image pairs from the SPOT 5 satellite's high-resolution stereoscopic (HRS) instrument acquired in 2004. The ice-free part of the accurate DEM from 1998 was used as a reference map for co-registration and correction of the vertical offset of the other DEMs. The average specific mass balance was estimated from the mean elevation difference between glaciated areas of the DEMs. The glacier mass balance declined significantly between the two periods: from -0.2 to 0.2 m yr(-1) w. eq. during the earlier period (1980s through 1998) to -1.8 to -1.5 m yr(-1) w. eq. for the more recent period (1998-2004). The declining mass balance is consistent with increased temperature over the two periods. The low mass balance and the small accumulation area ratio of Tindfjallajokull and Torfajokull indicate that they will disappear if the present-day climate continues. The future lowering rate of Eyjafjallajokull will, however, be influenced by the 2010 subglacial eruption in the Eyjafjallajokull volcano.