A squeezing flow viscometer was developed to characterize the rheological properties of fluorinated thermoplastics. The viscosities of CTFE (polychlorotrifluorethylene) and FEP (a copolymer of tetrafluoroethylene and hexafluoropropylene) were determined using the viscometer by assuming that the shear-rate dependent viscosity can be described by a power-law, a truncated power-law, or an Ellis model. The results were in agreement with the viscosities measured with steady shear cone-and-plate viscometry and oscillatory cone-and-plate rheometry. Although the squeezing flow behavior of the polymers can be well explained by the purely viscous models, the power-law model is valid only for a limited range of shear-rates whereas the other two models are useful over a relatively wide range.