We present InSAR observations of deformation due to two Ms = 6.6 earthquakes in the South Iceland Seismic Zone in June 2000. Coseismic deformation predominates in the ERS interferograms. Range change, due to mainly right-lateral strike-slip on N-S striking faults, amounting to more than 15 cm is observed, although displacement is mainly perpendicular to the satellite look direction. Using elastic dislocation models in a trial-and-error scheme, we find a best-fitting model that agrees well with the aftershock locations and moment magnitudes estimated from seismograms. The June 17 model has a fault patch 16 km long, 10 km deep, striking N05°E, dipping 86°, with a slip maximum of 2.40 m. The June 21 model has a vertical patch 15 km long, 9 km deep, striking N01°W, with a slip maximum of 2.15 m.