On September 7, 1999, a moderate (Mw=5.9) normal faulting earthquake occurred in the northwest of Athens (Hellas) causing heavy damages and casualties. Using interferometric combinations of ERS2 SAR images, we analyzed the coseismic deformation field. Two fringes are observed south of the Fili mountain, up to the coastline of the Elefsis gulf. They correspond to 56 mm increase in slant range. Modeling the earthquake as a dislocation in an elastic half-space, we inverted the interferometric data to assess the fault location and geometry and the amplitude of the coseismic slip. The model suggests ~300 mm slip on an 18 km long blind fault composed of two pieces. The intersection of the fault plane with the Earth surface is located in the Fili mountain with a ~N120¿ orientation. ¿ 2000 American Geophysical Union