Multi-megawatt wind turbines that are increasingly being used for higher and cheaper wind power generation have large, slender and extremely flexible rotor blades made of advanced composite materials. Safe and efficient design of these rotors requires an accurate modeling of the blade aeroelastic response under real wind conditions to include the effect of blade flexibility. This paper presents the results of the numerical simulations of the flow field around a 3-bladed horizontal axis wind turbine rotor and the blade aeroelastic response using a coupled computational fluid dynamics (CFD) and finite element analysis (FEA) approach. The blade has a NACA64 profile with a box-spar stiffener. The wind shear along the blade span and the effect of wake turbulence is included in the unsteady aerodynamic load calculation. The velocity field ahead and in the rotor wake is obtained for different mean wind speeds at the inlet. The time history of the flap-wise blade deformations is computed at different span locations. The wake turbulence was investigated by computing the turbulence intensity. Copyright © 2013 APCWE-VIII. All rights reserved. Publishedby Research Publishing, Singapore.