We propose a design for a polarization beam splitter based on the phenomenon of a photonic crystal directional coupler. The design consists of a honeycomb lattice arrangement of air holes of different radii in a silicon-on-insulator substrate exhibiting a complete photonic bandgap. The results obtained by the finite-difference time domain method show that the extinction ratio for transverse electric (TE) and transverse magnetic (TM) polarizations is 24.56 and 28.29 dB, respectively, at a wavelength of . The degree of polarization for TE polarization is 99.29% and for TM polarization is 99.70%. Hence, the proposed design can be efficiently used as a polarization splitter for on-chip integrated devices.