We show that index guided and photonic bandgap holey fibers of specific construction can be used as a wide-band fiber-optic polarizers. Similarly to traditional polarizing fibers, the operation principle of the index guided PCF polarizers is related to the difference in cut-off wavelengths of the two orthogonally polarized fundamental modes. Several fiber structures were analyzed and optimized for possibly highest polarization bandwidth. Furthermore, we investigated polarizing properties of four PBG PCFs with elliptical core. Our results show that after optimization of the cladding geometry, the polarization dependent loss in the analyzed PBG structures are so high that they can be used as fiber-optic polarizers in the full bandgap range