The seismic safety of 260 m high rock-fill dam in narrow and curved valley, located in seismically active area subjected to Maximum Credeble Earthquake (MCE) with Peak Ground Acceleration (PGA) 0.5g has been investigated. A sequential nonlinear static and nonlinear earthquake analysis has been carriedout using the Mohar-Coulomb material model for the rock-fill material. The high rock-fill dam is found to resist the most severe earthquake ground motion expected at the site. However, the dam undergoes some plastic deformations mostly at the u/s and d/s slopes which is not likely to lead any possible failure. The maximum settlement, peak accelerations and deformations are within acceptable limits under the postulated MCE and thus the dam is found to be seismically safe