This presentation will discuss a crystal plasticity based finite element model for prediction of deformation under cycle loading, leading to fatigue in Titanium alloys. The crystal plasticity model involves microstructural characterization and incorporation of crystallographic orientation distribution to models, based on accurate microstructural data obtained by orientation imaging microscopy. A crack nucleation criterion is developed based on an effective stress measure on a slip plane in the hard grain as well as the dislocation pileup in the neighboring soft grains. The proposed criterion is calibrated and validated with some experimental observations. A wavelet based multi-time scale methodology has also been developed which significantly reduces the computational time till crack initiation. The fundamental idea is to decouple the fine and coarse time scale responses at the constitutive level by applying wavelet decomposition to the primary displacement variable. The resulting modified finite element scheme along with the equivalent coarse time scale equations enable one to jump over many cycles in one step resulting in significant savings in the computational time.