A full-vectorial analysis of optical dielectric waveguide bends using the finite-difference method has been developed. The formulation was based on the transverse electric field components, Er and Ez. To set up the boundary conditions at each dielectric interface, the continuity of Eθ, Hθ, and the tangential component of the electric field, and the discontinuity of the normal component of the electric field were satisfied. The finite-difference scheme was modified to satisfy these boundary conditions. The results of the analysis using the current method is compared with previous results. The optimal offset for 90° bends was obtained, and the losses for these optimal bend structures are also presented.