A study was conducted, to address the problem of estimating short-term deflections in reinforced concrete (RC) two-way slabs, using finite element analysis with appropriate stiffness modifiers. The study proposed a modified Branson's formulation, to account for the complex effects of flexural cracking and tension stiffening, along with a simple modification to account for torsional cracking. The parameters in proposed formulation are determined empirically and the procedure validated by 23 investigative loading-deflection data sets. The proposed formulation stated that the stiffness changes for an RC two-way slab, subjected to bi-directional bending and torsion throughout the slab. It was demonstrated that the stiffness changes throughout the slab, due to cracking, depending on the magnitude of the principal tensile stress. The study also demonstrated that the idea is, top retain the assumed isotropic behavior in the elasticity in the proposed approach.