An investigation has been carried out into possible differences in personal Higgins- and Dewell-type cyclone performance when sampling plate-like particles such as talc or metallic flakes, in contrast to spherical particles. Theoretical calculations indicate that particle shape effects will be dominated by particles assuming a preferred orientation that is different in the respiratory system and the cyclone. Experimental comparisons with MRE 113A horizontal elutriators indicated talc particles to align randomly in the cyclone. If a maximum drag orientation is assumed in the respiratory system, this will lead to the respirable fraction of an aerosol of plate-like particles being underestimated by approximately 15% on average. However, more information is needed on how non-spherical particles behave in the respiratory tract before the degree of undersampling can be further quantified.